402978816 has 72 divisors (see below), whose sum is σ = 1163930040. Its totient is φ = 134320128.

The previous prime is 402978773. The next prime is 402978817. The reversal of 402978816 is 618879204.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×402978816² = 324783852289523712, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402978817) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7501 + ... + 29363.

It is an arithmetic number, because the mean of its divisors is an integer number (16165695).

Almost surely, 2^402978816 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 402978816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (581965020).

402978816 is an abundant number, since it is smaller than the sum of its proper divisors (760951224).

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

402978816 is a wasteful number, since it uses less digits than its factorization.

402978816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21891 (or 21868 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 402978816 is about 20074.3322678489. The cubic root of 402978816 is about 738.6307868479.

The spelling of 402978816 in words is "four hundred two million, nine hundred seventy-eight thousand, eight hundred sixteen".