21504001553 has 8 divisors (see below), whose sum is σ = 21540774528. Its totient is φ = 21467260144.

The previous prime is 21504001523. The next prime is 21504001567. The reversal of 21504001553 is 35510040512.

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 21504001553 - 2¹² = 21503997457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21504001523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1634600 + ... + 1647702.

It is an arithmetic number, because the mean of its divisors is an integer number (2692596816).

Almost surely, 2^21504001553 is an apocalyptic number.

It is an amenable number.

21504001553 is a deficient number, since it is larger than the sum of its proper divisors (36772975).

21504001553 is a wasteful number, since it uses less digits than its factorization.

21504001553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15783.

The product of its (nonzero) digits is 3000, while the sum is 26.

The spelling of 21504001553 in words is "twenty-one billion, five hundred four million, one thousand, five hundred fifty-three".