21216046235655 has 32 divisors (see below), whose sum is σ = 34740068622336. Its totient is φ = 11050501601664.

The previous prime is 21216046235651. The next prime is 21216046235689. The reversal of 21216046235655 is 55653264061212.

It is not a de Polignac number, because 21216046235655 - 2² = 21216046235651 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216046235651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2178234 + ... + 6868536.

It is an arithmetic number, because the mean of its divisors is an integer number (1085627144448).

Almost surely, 2^{21216046235655} is an apocalyptic number.

21216046235655 is a deficient number, since it is larger than the sum of its proper divisors (13524022386681).

21216046235655 is a wasteful number, since it uses less digits than its factorization.

21216046235655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4697367.

The product of its (nonzero) digits is 2592000, while the sum is 48.

The spelling of 21216046235655 in words is "twenty-one trillion, two hundred sixteen billion, forty-six million, two hundred thirty-five thousand, six hundred fifty-five".