21370522440 has 128 divisors (see below), whose sum is σ = 64644480000. Its totient is φ = 5651635968.

The previous prime is 21370522423. The next prime is 21370522507. The reversal of 21370522440 is 4422507312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21370522398 and 21370522407.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8285071 + ... + 8287649.

It is an arithmetic number, because the mean of its divisors is an integer number (505035000).

Almost surely, 2^21370522440 is an apocalyptic number.

21370522440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21370522440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32322240000).

21370522440 is an abundant number, since it is smaller than the sum of its proper divisors (43273957560).

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

21370522440 is a wasteful number, since it uses less digits than its factorization.

21370522440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3139 (or 3135 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 30.

The spelling of 21370522440 in words is "twenty-one billion, three hundred seventy million, five hundred twenty-two thousand, four hundred forty".