21974904 has 96 divisors (see below), whose sum is σ = 69264000. Its totient is φ = 6163776.

The previous prime is 21974899. The next prime is 21974917. The reversal of 21974904 is 40947912.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 29367 + ... + 30105.

It is an arithmetic number, because the mean of its divisors is an integer number (721500).

Almost surely, 2^21974904 is an apocalyptic number.

21974904 is a gapful number since it is divisible by the number (24) 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 21974904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34632000).

21974904 is an abundant number, since it is smaller than the sum of its proper divisors (47289096).

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

21974904 is a wasteful number, since it uses less digits than its factorization.

21974904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817 (or 810 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21974904 is about 4687.7397538686. The cubic root of 21974904 is about 280.0973471040.

The spelling of 21974904 in words is "twenty-one million, nine hundred seventy-four thousand, nine hundred four".