21666364556153 has 4 divisors (see below), whose sum is σ = 21668689532160. Its totient is φ = 21664039580148.

The previous prime is 21666364556147. The next prime is 21666364556203. The reversal of 21666364556153 is 35165546366612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21666364556153 - 2⁸ = 21666364555897 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21666364556092 and 21666364556101.

It is not an unprimeable number, because it can be changed into a prime (21666364556453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1162474025 + ... + 1162492662.

It is an arithmetic number, because the mean of its divisors is an integer number (5417172383040).

Almost surely, 2^{21666364556153} is an apocalyptic number.

It is an amenable number.

21666364556153 is a deficient number, since it is larger than the sum of its proper divisors (2324976007).

21666364556153 is an equidigital number, since it uses as much as digits as its factorization.

21666364556153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2324976006.

The product of its digits is 69984000, while the sum is 59.

The spelling of 21666364556153 in words is "twenty-one trillion, six hundred sixty-six billion, three hundred sixty-four million, five hundred fifty-six thousand, one hundred fifty-three".