21677204643 has 4 divisors (see below), whose sum is σ = 28902939528. Its totient is φ = 14451469760.

The previous prime is 21677204641. The next prime is 21677204701. The reversal of 21677204643 is 34640277612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21677204643 - 2¹ = 21677204641 is a prime.

It is a super-2 number, since 2×21677204643² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21677204595 and 21677204604.

It is not an unprimeable number, because it can be changed into a prime (21677204641) 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, 3612867438 + ... + 3612867443.

It is an arithmetic number, because the mean of its divisors is an integer number (7225734882).

Almost surely, 2^21677204643 is an apocalyptic number.

21677204643 is a deficient number, since it is larger than the sum of its proper divisors (7225734885).

21677204643 is an equidigital number, since it uses as much as digits as its factorization.

21677204643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7225734884.

The product of its (nonzero) digits is 338688, while the sum is 42.

The spelling of 21677204643 in words is "twenty-one billion, six hundred seventy-seven million, two hundred four thousand, six hundred forty-three".