21355462604661 has 4 divisors (see below), whose sum is σ = 28473950139552. Its totient is φ = 14236975069772.

The previous prime is 21355462604653. The next prime is 21355462604669. The reversal of 21355462604661 is 16640626455312.

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 an interprime number because it is at equal distance from previous prime (21355462604653) and next prime (21355462604669).

It is a cyclic number.

It is not a de Polignac number, because 21355462604661 - 2³ = 21355462604653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355462604669) 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, 3559243767441 + ... + 3559243767446.

It is an arithmetic number, because the mean of its divisors is an integer number (7118487534888).

Almost surely, 2^{21355462604661} is an apocalyptic number.

It is an amenable number.

21355462604661 is a deficient number, since it is larger than the sum of its proper divisors (7118487534891).

21355462604661 is an equidigital number, since it uses as much as digits as its factorization.

21355462604661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7118487534890.

The product of its (nonzero) digits is 6220800, while the sum is 51.

The spelling of 21355462604661 in words is "twenty-one trillion, three hundred fifty-five billion, four hundred sixty-two million, six hundred four thousand, six hundred sixty-one".