20422640 has 40 divisors (see below), whose sum is σ = 54267360. Its totient is φ = 7001856.

The previous prime is 20422637. The next prime is 20422651. The reversal of 20422640 is 4622402.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17675 + ... + 18794.

It is an arithmetic number, because the mean of its divisors is an integer number (1356684).

Almost surely, 2^20422640 is an apocalyptic number.

20422640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20422640 is an abundant number, since it is smaller than the sum of its proper divisors (33844720).

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

20422640 is a wasteful number, since it uses less digits than its factorization.

20422640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36489 (or 36483 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 20422640 is about 4519.1415113935. The cubic root of 20422640 is about 273.3404849738.

The spelling of 20422640 in words is "twenty million, four hundred twenty-two thousand, six hundred forty".