21017155671512 has 64 divisors (see below), whose sum is σ = 52910321990400. Its totient is φ = 7558617421440.

The previous prime is 21017155671509. The next prime is 21017155671553. The reversal of 21017155671512 is 21517655171012.

It is a super-2 number, since 2×21017155671512² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1312251962 + ... + 1312267977.

It is an arithmetic number, because the mean of its divisors is an integer number (826723781100).

Almost surely, 2^{21017155671512} is an apocalyptic number.

21017155671512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21017155671512 is an abundant number, since it is smaller than the sum of its proper divisors (31893166318888).

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

21017155671512 is a wasteful number, since it uses less digits than its factorization.

21017155671512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2624519976 (or 2624519972 counting only the distinct ones).

The product of its (nonzero) digits is 147000, while the sum is 44.

The spelling of 21017155671512 in words is "twenty-one trillion, seventeen billion, one hundred fifty-five million, six hundred seventy-one thousand, five hundred twelve".