21939948 has 18 divisors (see below), whose sum is σ = 55459404. Its totient is φ = 7313304.

The previous prime is 21939937. The next prime is 21939977. The reversal of 21939948 is 84993912.

21939948 is a `hidden beast` number, since 219 + 399 + 48 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21939948² = 962722636485408, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 304686 + ... + 304757.

It is an arithmetic number, because the mean of its divisors is an integer number (3081078).

Almost surely, 2^21939948 is an apocalyptic number.

It is an amenable number.

21939948 is an abundant number, since it is smaller than the sum of its proper divisors (33519456).

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

21939948 is a wasteful number, since it uses less digits than its factorization.

21939948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609453 (or 609448 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 21939948 is about 4684.0098206558. The cubic root of 21939948 is about 279.9487491231.

The spelling of 21939948 in words is "twenty-one million, nine hundred thirty-nine thousand, nine hundred forty-eight".