21506216610 has 64 divisors (see below), whose sum is σ = 52309209600. Its totient is φ = 5657962752.

The previous prime is 21506216573. The next prime is 21506216617. The reversal of 21506216610 is 1661260512.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21506216617) 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, 3952812 + ... + 3958248.

It is an arithmetic number, because the mean of its divisors is an integer number (817331400).

Almost surely, 2^21506216610 is an apocalyptic number.

21506216610 is an abundant number, since it is smaller than the sum of its proper divisors (30802992990).

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

21506216610 is a wasteful number, since it uses less digits than its factorization.

21506216610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7195.

The product of its (nonzero) digits is 4320, while the sum is 30.

The spelling of 21506216610 in words is "twenty-one billion, five hundred six million, two hundred sixteen thousand, six hundred ten".