21554534251 has 8 divisors (see below), whose sum is σ = 21922570800. Its totient is φ = 21186588000.

The previous prime is 21554534237. The next prime is 21554534257. The reversal of 21554534251 is 15243545512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21554534251 - 2⁹ = 21554533739 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21554534251.

It is not an unprimeable number, because it can be changed into a prime (21554534257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 607501 + ... + 642001.

It is an arithmetic number, because the mean of its divisors is an integer number (2740321350).

Almost surely, 2^21554534251 is an apocalyptic number.

21554534251 is a deficient number, since it is larger than the sum of its proper divisors (368036549).

21554534251 is a wasteful number, since it uses less digits than its factorization.

21554534251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45149.

The product of its digits is 120000, while the sum is 37.

The spelling of 21554534251 in words is "twenty-one billion, five hundred fifty-four million, five hundred thirty-four thousand, two hundred fifty-one".