21002400402 has 16 divisors (see below), whose sum is σ = 42172153632. Its totient is φ = 6972908000.

The previous prime is 21002400373. The next prime is 21002400413. The reversal of 21002400402 is 20400420012.

It is a super-2 number, since 2×21002400402² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6971403 + ... + 6974414.

It is an arithmetic number, because the mean of its divisors is an integer number (2635759602).

Almost surely, 2^21002400402 is an apocalyptic number.

21002400402 is an abundant number, since it is smaller than the sum of its proper divisors (21169753230).

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

21002400402 is a wasteful number, since it uses less digits than its factorization.

21002400402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13946073.

The product of its (nonzero) digits is 128, while the sum is 15.

Adding to 21002400402 its reverse (20400420012), we get a palindrome (41402820414).

The spelling of 21002400402 in words is "twenty-one billion, two million, four hundred thousand, four hundred two".