21651005554 has 32 divisors (see below), whose sum is σ = 35533956096. Its totient is φ = 9849538560.

The previous prime is 21651005543. The next prime is 21651005591. The reversal of 21651005554 is 45550015612.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1025634 + ... + 1046530.

It is an arithmetic number, because the mean of its divisors is an integer number (1110436128).

Almost surely, 2^21651005554 is an apocalyptic number.

21651005554 is a deficient number, since it is larger than the sum of its proper divisors (13882950542).

21651005554 is a wasteful number, since it uses less digits than its factorization.

21651005554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21930.

The product of its (nonzero) digits is 30000, while the sum is 34.

The spelling of 21651005554 in words is "twenty-one billion, six hundred fifty-one million, five thousand, five hundred fifty-four".