21542231550 has 96 divisors (see below), whose sum is σ = 61083804672. Its totient is φ = 4921764480.

The previous prime is 21542231539. The next prime is 21542231561. The reversal of 21542231550 is 5513224512.

It is an interprime number because it is at equal distance from previous prime (21542231539) and next prime (21542231561).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4683852 + ... + 4688448.

It is an arithmetic number, because the mean of its divisors is an integer number (636289632).

Almost surely, 2^21542231550 is an apocalyptic number.

21542231550 is an abundant number, since it is smaller than the sum of its proper divisors (39541573122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21542231550 is a wasteful number, since it uses less digits than its factorization.

21542231550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9082 (or 9077 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 30.

The spelling of 21542231550 in words is "twenty-one billion, five hundred forty-two million, two hundred thirty-one thousand, five hundred fifty".