21261011656610 has 32 divisors (see below), whose sum is σ = 41896418277312. Its totient is φ = 7703957954880.

The previous prime is 21261011656603. The next prime is 21261011656631. The reversal of 21261011656610 is 1665611016212.

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, 341456369 + ... + 341518628.

It is an arithmetic number, because the mean of its divisors is an integer number (1309263071166).

Almost surely, 2^{21261011656610} is an apocalyptic number.

21261011656610 is a deficient number, since it is larger than the sum of its proper divisors (20635406620702).

21261011656610 is a wasteful number, since it uses less digits than its factorization.

21261011656610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682975298.

The product of its (nonzero) digits is 25920, while the sum is 38.

The spelling of 21261011656610 in words is "twenty-one trillion, two hundred sixty-one billion, eleven million, six hundred fifty-six thousand, six hundred ten".