210864902661 has 48 divisors (see below), whose sum is σ = 350876448000. Its totient is φ = 119533296384.

The previous prime is 210864902639. The next prime is 210864902693. The reversal of 210864902661 is 166209468012.

210864902661 is a `hidden beast` number, since 2 + 1 + 0 + 86 + 490 + 26 + 61 = 666.

It is not a de Polignac number, because 210864902661 - 2⁷ = 210864902533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210864902621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7580200 + ... + 7607966.

It is an arithmetic number, because the mean of its divisors is an integer number (7309926000).

Almost surely, 2^210864902661 is an apocalyptic number.

210864902661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

210864902661 is a deficient number, since it is larger than the sum of its proper divisors (140011545339).

210864902661 is a wasteful number, since it uses less digits than its factorization.

210864902661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28738 (or 28735 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 210864902661 in words is "two hundred ten billion, eight hundred sixty-four million, nine hundred two thousand, six hundred sixty-one".