20915940 has 48 divisors (see below), whose sum is σ = 59818752. Its totient is φ = 5458176.

The previous prime is 20915929. The next prime is 20915953. The reversal of 20915940 is 4951902.

It is a happy number.

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 = 20915898 and 20915907.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 889 + ... + 6528.

It is an arithmetic number, because the mean of its divisors is an integer number (1246224).

Almost surely, 2^20915940 is an apocalyptic number.

20915940 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 20915940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29909376).

20915940 is an abundant number, since it is smaller than the sum of its proper divisors (38902812).

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

20915940 is a wasteful number, since it uses less digits than its factorization.

20915940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7476 (or 7474 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 20915940 is about 4573.3948003644. The cubic root of 20915940 is about 275.5238060550.

The spelling of 20915940 in words is "twenty million, nine hundred fifteen thousand, nine hundred forty".