21623551464542 has 4 divisors (see below), whose sum is σ = 32435327196816. Its totient is φ = 10811775732270.

The previous prime is 21623551464511. The next prime is 21623551464577. The reversal of 21623551464542 is 24546415532612.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5405887866134 + ... + 5405887866137.

It is an arithmetic number, because the mean of its divisors is an integer number (8108831799204).

Almost surely, 2^{21623551464542} is an apocalyptic number.

21623551464542 is a deficient number, since it is larger than the sum of its proper divisors (10811775732274).

21623551464542 is a wasteful number, since it uses less digits than its factorization.

21623551464542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10811775732273.

The product of its digits is 6912000, while the sum is 50.

The spelling of 21623551464542 in words is "twenty-one trillion, six hundred twenty-three billion, five hundred fifty-one million, four hundred sixty-four thousand, five hundred forty-two".