21211556610 has 16 divisors (see below), whose sum is σ = 50907735936. Its totient is φ = 5656415088.

The previous prime is 21211556573. The next prime is 21211556617. The reversal of 21211556610 is 1665511212.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 707051887 = 21211556610 / (2 + 1 + 2 + 1 + 1 + 5 + 5 + 6 + 6 + 1 + 0).

It is not an unprimeable number, because it can be changed into a prime (21211556617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 353525914 + ... + 353525973.

It is an arithmetic number, because the mean of its divisors is an integer number (3181733496).

Almost surely, 2^21211556610 is an apocalyptic number.

21211556610 is an abundant number, since it is smaller than the sum of its proper divisors (29696179326).

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

21211556610 is a wasteful number, since it uses less digits than its factorization.

21211556610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707051897.

The product of its (nonzero) digits is 3600, while the sum is 30.

The spelling of 21211556610 in words is "twenty-one billion, two hundred eleven million, five hundred fifty-six thousand, six hundred ten".