21939958 has 4 divisors (see below), whose sum is σ = 32909940. Its totient is φ = 10969978.

The previous prime is 21939937. The next prime is 21939977. The reversal of 21939958 is 85993912.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5484988 + ... + 5484991.

It is an arithmetic number, because the mean of its divisors is an integer number (8227485).

Almost surely, 2^21939958 is an apocalyptic number.

21939958 is a deficient number, since it is larger than the sum of its proper divisors (10969982).

21939958 is a wasteful number, since it uses less digits than its factorization.

21939958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10969981.

The product of its digits is 174960, while the sum is 46.

The square root of 21939958 is about 4684.0108881171. The cubic root of 21939958 is about 279.9487916556.

The spelling of 21939958 in words is "twenty-one million, nine hundred thirty-nine thousand, nine hundred fifty-eight".