21973406 has 32 divisors (see below), whose sum is σ = 40877760. Its totient is φ = 8626176.

The previous prime is 21973379. The next prime is 21973423. The reversal of 21973406 is 60437912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28190 + ... + 28958.

It is an arithmetic number, because the mean of its divisors is an integer number (1277430).

Almost surely, 2^21973406 is an apocalyptic number.

21973406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21973406 is a deficient number, since it is larger than the sum of its proper divisors (18904354).

21973406 is a wasteful number, since it uses less digits than its factorization.

21973406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 21973406 is about 4687.5799726511. The cubic root of 21973406 is about 280.0909823380.

The spelling of 21973406 in words is "twenty-one million, nine hundred seventy-three thousand, four hundred six".