21700665051 has 16 divisors (see below), whose sum is σ = 31207249920. Its totient is φ = 13333975200.

The previous prime is 21700665029. The next prime is 21700665079. The reversal of 21700665051 is 15056600712.

It is not a de Polignac number, because 21700665051 - 2¹¹ = 21700663003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21700665011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 396475 + ... + 447876.

It is an arithmetic number, because the mean of its divisors is an integer number (1950453120).

Almost surely, 2^21700665051 is an apocalyptic number.

21700665051 is a deficient number, since it is larger than the sum of its proper divisors (9506584869).

21700665051 is a wasteful number, since it uses less digits than its factorization.

21700665051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845026.

The product of its (nonzero) digits is 12600, while the sum is 33.

The spelling of 21700665051 in words is "twenty-one billion, seven hundred million, six hundred sixty-five thousand, fifty-one".