21000202170 has 64 divisors (see below), whose sum is σ = 54269792640. Its totient is φ = 5181298688.

The previous prime is 21000202169. The next prime is 21000202213. The reversal of 21000202170 is 7120200012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 318867 + ... + 379046.

It is an arithmetic number, because the mean of its divisors is an integer number (847965510).

Almost surely, 2^21000202170 is an apocalyptic number.

21000202170 is an abundant number, since it is smaller than the sum of its proper divisors (33269590470).

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

21000202170 is a wasteful number, since it uses less digits than its factorization.

21000202170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697999.

The product of its (nonzero) digits is 56, while the sum is 15.

Adding to 21000202170 its reverse (7120200012), we get a palindrome (28120402182).

The spelling of 21000202170 in words is "twenty-one billion, two hundred two thousand, one hundred seventy".