20974940 has 72 divisors (see below), whose sum is σ = 54295920. Its totient is φ = 6763008.

The previous prime is 20974937. The next prime is 20974951. The reversal of 20974940 is 4947902.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 20974940.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16031 + ... + 17289.

It is an arithmetic number, because the mean of its divisors is an integer number (754110).

Almost surely, 2^20974940 is an apocalyptic number.

20974940 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 20974940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27147960).

20974940 is an abundant number, since it is smaller than the sum of its proper divisors (33320980).

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

20974940 is a wasteful number, since it uses less digits than its factorization.

20974940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1299 (or 1290 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 20974940 is about 4579.8406085802. The cubic root of 20974940 is about 275.7826300827.

The spelling of 20974940 in words is "twenty million, nine hundred seventy-four thousand, nine hundred forty".