21645717101642 has 16 divisors (see below), whose sum is σ = 33880433716800. Its totient is φ = 10352244220032.

The previous prime is 21645717101629. The next prime is 21645717101651. The reversal of 21645717101642 is 24610171754612.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8224109 + ... + 10532207.

It is an arithmetic number, because the mean of its divisors is an integer number (2117527107300).

Almost surely, 2^{21645717101642} is an apocalyptic number.

21645717101642 is a deficient number, since it is larger than the sum of its proper divisors (12234716615158).

21645717101642 is a wasteful number, since it uses less digits than its factorization.

21645717101642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2511997.

The product of its (nonzero) digits is 564480, while the sum is 47.

The spelling of 21645717101642 in words is "twenty-one trillion, six hundred forty-five billion, seven hundred seventeen million, one hundred one thousand, six hundred forty-two".