21797312156 has 12 divisors (see below), whose sum is σ = 38146336368. Its totient is φ = 10898358912.

The previous prime is 21797312111. The next prime is 21797312179. The reversal of 21797312156 is 65121379712.

It is a super-2 number, since 2×21797312156² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222380 + ... + 305036.

It is an arithmetic number, because the mean of its divisors is an integer number (3178861364).

Almost surely, 2^21797312156 is an apocalyptic number.

It is an amenable number.

21797312156 is a deficient number, since it is larger than the sum of its proper divisors (16349024212).

21797312156 is a wasteful number, since it uses less digits than its factorization.

21797312156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148588 (or 148586 counting only the distinct ones).

The product of its digits is 158760, while the sum is 44.

The spelling of 21797312156 in words is "twenty-one billion, seven hundred ninety-seven million, three hundred twelve thousand, one hundred fifty-six".