21291738100 has 36 divisors (see below), whose sum is σ = 47277571264. Its totient is φ = 8318630880.

The previous prime is 21291738073. The next prime is 21291738109. The reversal of 21291738100 is 183719212.

It is a super-2 number, since 2×21291738100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21291738109) 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, 2471484 + ... + 2480083.

Almost surely, 2^21291738100 is an apocalyptic number.

21291738100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21291738100 is an abundant number, since it is smaller than the sum of its proper divisors (25985833164).

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

21291738100 is a wasteful number, since it uses less digits than its factorization.

21291738100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4951624 (or 4951617 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 34.

The spelling of 21291738100 in words is "twenty-one billion, two hundred ninety-one million, seven hundred thirty-eight thousand, one hundred".