400779540 has 144 divisors (see below), whose sum is σ = 1462581120. Its totient is φ = 86780160.

The previous prime is 400779499. The next prime is 400779569. The reversal of 400779540 is 45977004.

It is a happy number.

400779540 is a `hidden beast` number, since 40 + 0 + 7 + 79 + 540 = 666.

It is a super-2 number, since 2×400779540² = 321248479365223200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 400779495 and 400779504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15570 + ... + 32310.

Almost surely, 2^400779540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400779540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (731290560).

400779540 is an abundant number, since it is smaller than the sum of its proper divisors (1061801580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

400779540 is a wasteful number, since it uses less digits than its factorization.

400779540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16782 (or 16777 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 400779540 is about 20019.4790142001. The cubic root of 400779540 is about 737.2846307831.

The spelling of 400779540 in words is "four hundred million, seven hundred seventy-nine thousand, five hundred forty".