21791000120 has 32 divisors (see below), whose sum is σ = 49106297520. Its totient is φ = 8702791680.

The previous prime is 21791000081. The next prime is 21791000131. The reversal of 21791000120 is 2100019712.

It is a congruent number.

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, 399302 + ... + 450581.

Almost surely, 2^21791000120 is an apocalyptic number.

21791000120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21791000120 is an abundant number, since it is smaller than the sum of its proper divisors (27315297400).

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

21791000120 is a wasteful number, since it uses less digits than its factorization.

21791000120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850535 (or 850531 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 23.

Adding to 21791000120 its reverse (2100019712), we get a palindrome (23891019832).

The spelling of 21791000120 in words is "twenty-one billion, seven hundred ninety-one million, one hundred twenty", and thus it is an aban number.