400287778489 has 3 divisors (see below), whose sum is σ = 400288411173. Its totient is φ = 400287145806.

The previous prime is 400287778481. The next prime is 400287778493. The reversal of 400287778489 is 984877782004.

The square root of 400287778489 is 632683.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 400287778489 - 2³ = 400287778481 is a prime.

It is a super-2 number, since 2×400287778489² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 400287778489.

It is not an unprimeable number, because it can be changed into a prime (400287778481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 316342 + ... + 949024.

It is an arithmetic number, because the mean of its divisors is an integer number (133429470391).

Almost surely, 2^400287778489 is an apocalyptic number.

400287778489 is the 632683-rd square number.

400287778489 is the 316342-nd centered octagonal number.

It is an amenable number.

400287778489 is a deficient number, since it is larger than the sum of its proper divisors (632684).

400287778489 is an frugal number, since it uses more digits than its factorization.

400287778489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1265366 (or 632683 counting only the distinct ones).

The product of its (nonzero) digits is 50577408, while the sum is 64.

Multiplying 400287778489 by its sum of digits (64), we get a square (25618417823296 = 5061464²).

The spelling of 400287778489 in words is "four hundred billion, two hundred eighty-seven million, seven hundred seventy-eight thousand, four hundred eighty-nine".