21038561901 has 24 divisors (see below), whose sum is σ = 34734286080. Its totient is φ = 12020664096.

The previous prime is 21038561849. The next prime is 21038561917. The reversal of 21038561901 is 10916583012.

21038561901 is a `hidden beast` number, since 2 + 1 + 0 + 3 + 8 + 561 + 90 + 1 = 666.

It is not a de Polignac number, because 21038561901 - 2¹⁰ = 21038560877 is a prime.

It is a super-3 number, since 3×21038561901³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21038561941) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 849571 + ... + 873983.

It is an arithmetic number, because the mean of its divisors is an integer number (1447261920).

Almost surely, 2^21038561901 is an apocalyptic number.

21038561901 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21038561901 is a deficient number, since it is larger than the sum of its proper divisors (13695724179).

21038561901 is a wasteful number, since it uses less digits than its factorization.

21038561901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38105 (or 38102 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The spelling of 21038561901 in words is "twenty-one billion, thirty-eight million, five hundred sixty-one thousand, nine hundred one".