21550322511 has 8 divisors (see below), whose sum is σ = 31926403760. Its totient is φ = 14366881656.

The previous prime is 21550322503. The next prime is 21550322539. The reversal of 21550322511 is 11522305512.

It is not a de Polignac number, because 21550322511 - 2³ = 21550322503 is a prime.

It is a super-2 number, since 2×21550322511² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 798160093 = 21550322511 / (2 + 1 + 5 + 5 + 0 + 3 + 2 + 2 + 5 + 1 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550322011) 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, 399080020 + ... + 399080073.

It is an arithmetic number, because the mean of its divisors is an integer number (3990800470).

Almost surely, 2^21550322511 is an apocalyptic number.

21550322511 is a deficient number, since it is larger than the sum of its proper divisors (10376081249).

21550322511 is an equidigital number, since it uses as much as digits as its factorization.

21550322511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798160102 (or 798160096 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 21550322511 in words is "twenty-one billion, five hundred fifty million, three hundred twenty-two thousand, five hundred eleven".