402390981 has 6 divisors (see below), whose sum is σ = 581231430. Its totient is φ = 268260648.

The previous prime is 402390973. The next prime is 402391001. The reversal of 402390981 is 189093204.

It can be written as a sum of positive squares in only one way, i.e., 211702500 + 190688481 = 14550^2 + 13809^2 .

It is not a de Polignac number, because 402390981 - 2³ = 402390973 is a prime.

It is a super-3 number, since 3×402390981³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402390971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22355046 + ... + 22355063.

It is an arithmetic number, because the mean of its divisors is an integer number (96871905).

Almost surely, 2^402390981 is an apocalyptic number.

It is an amenable number.

402390981 is a deficient number, since it is larger than the sum of its proper divisors (178840449).

402390981 is a wasteful number, since it uses less digits than its factorization.

402390981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44710115 (or 44710112 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 402390981 is about 20059.6854661283. The cubic root of 402390981 is about 738.2714591734.

The spelling of 402390981 in words is "four hundred two million, three hundred ninety thousand, nine hundred eighty-one".