21506730621115 has 16 divisors (see below), whose sum is σ = 27626843980800. Its totient is φ = 16023569500512.

The previous prime is 21506730621043. The next prime is 21506730621161. The reversal of 21506730621115 is 51112603760512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21506730621115 - 2⁷ = 21506730620987 is a prime.

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, 1918525227 + ... + 1918536436.

It is an arithmetic number, because the mean of its divisors is an integer number (1726677748800).

Almost surely, 2^{21506730621115} is an apocalyptic number.

21506730621115 is a deficient number, since it is larger than the sum of its proper divisors (6120113359685).

21506730621115 is a wasteful number, since it uses less digits than its factorization.

21506730621115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3837061746.

The product of its (nonzero) digits is 75600, while the sum is 40.

The spelling of 21506730621115 in words is "twenty-one trillion, five hundred six billion, seven hundred thirty million, six hundred twenty-one thousand, one hundred fifteen".