21641903402 has 24 divisors (see below), whose sum is σ = 37835483940. Its totient is φ = 9257277120.

The previous prime is 21641903377. The next prime is 21641903407. The reversal of 21641903402 is 20430914612.

It can be written as a sum of positive squares in 2 ways, for example, as 20558111161 + 1083792241 = 143381^2 + 32921^2 .

It is a super-2 number, since 2×21641903402² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21641903407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 160877 + ... + 262992.

Almost surely, 2^21641903402 is an apocalyptic number.

21641903402 is a deficient number, since it is larger than the sum of its proper divisors (16193580538).

21641903402 is a wasteful number, since it uses less digits than its factorization.

21641903402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424406 (or 424399 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The spelling of 21641903402 in words is "twenty-one billion, six hundred forty-one million, nine hundred three thousand, four hundred two".