21755222740 has 12 divisors (see below), whose sum is σ = 45685967796. Its totient is φ = 8702089088.

The previous prime is 21755222707. The next prime is 21755222747. The reversal of 21755222740 is 4722255712.

It can be written as a sum of positive squares in 2 ways, for example, as 12037600656 + 9717622084 = 109716^2 + 98578^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21755222740.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21755222747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543880549 + ... + 543880588.

It is an arithmetic number, because the mean of its divisors is an integer number (3807163983).

Almost surely, 2^21755222740 is an apocalyptic number.

21755222740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21755222740 is an abundant number, since it is smaller than the sum of its proper divisors (23930745056).

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

21755222740 is a wasteful number, since it uses less digits than its factorization.

21755222740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1087761146 (or 1087761144 counting only the distinct ones).

The product of its (nonzero) digits is 78400, while the sum is 37.

The spelling of 21755222740 in words is "twenty-one billion, seven hundred fifty-five million, two hundred twenty-two thousand, seven hundred forty".