21939946 has 24 divisors (see below), whose sum is σ = 40301280. Its totient is φ = 8907192.

The previous prime is 21939937. The next prime is 21939977. The reversal of 21939946 is 64993912.

It is a super-2 number, since 2×21939946² = 962722460965832, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4030 + ... + 7753.

It is an arithmetic number, because the mean of its divisors is an integer number (1679220).

Almost surely, 2^21939946 is an apocalyptic number.

21939946 is a deficient number, since it is larger than the sum of its proper divisors (18361334).

21939946 is a wasteful number, since it uses less digits than its factorization.

21939946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11818 (or 11811 counting only the distinct ones).

The product of its digits is 104976, while the sum is 43.

The square root of 21939946 is about 4684.0096071635. The cubic root of 21939946 is about 279.9487406166.

The spelling of 21939946 in words is "twenty-one million, nine hundred thirty-nine thousand, nine hundred forty-six".