840451399 has 4 divisors (see below), whose sum is σ = 847889136. Its totient is φ = 833013664.

The previous prime is 840451373. The next prime is 840451421. The reversal of 840451399 is 993154048.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 840451399 - 2²⁵ = 806896967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840451319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3718699 + ... + 3718924.

It is an arithmetic number, because the mean of its divisors is an integer number (211972284).

Almost surely, 2^840451399 is an apocalyptic number.

840451399 is a deficient number, since it is larger than the sum of its proper divisors (7437737).

840451399 is a wasteful number, since it uses less digits than its factorization.

840451399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7437736.

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 840451399 is about 28990.5398190513. The cubic root of 840451399 is about 943.7077786822.

The spelling of 840451399 in words is "eight hundred forty million, four hundred fifty-one thousand, three hundred ninety-nine".