21811754550 has 24 divisors (see below), whose sum is σ = 54093151656. Its totient is φ = 5816467840.

The previous prime is 21811754537. The next prime is 21811754563. The reversal of 21811754550 is 5545711812.

It is an interprime number because it is at equal distance from previous prime (21811754537) and next prime (21811754563).

It is a junction number, because it is equal to n+sod(n) for n = 21811754499 and 21811754508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 72705699 + ... + 72705998.

It is an arithmetic number, because the mean of its divisors is an integer number (2253881319).

Almost surely, 2^21811754550 is an apocalyptic number.

21811754550 is an abundant number, since it is smaller than the sum of its proper divisors (32281397106).

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

21811754550 is a wasteful number, since it uses less digits than its factorization.

21811754550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145411712 (or 145411707 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 39.

The spelling of 21811754550 in words is "twenty-one billion, eight hundred eleven million, seven hundred fifty-four thousand, five hundred fifty".