21913933 has 2 divisors, whose sum is σ = 21913934. Its totient is φ = 21913932.

The previous prime is 21913861. The next prime is 21913951. The reversal of 21913933 is 33931912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21501769 + 412164 = 4637^2 + 642^2 .

It is a cyclic number.

It is not a de Polignac number, because 21913933 - 2¹⁷ = 21782861 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21913895 and 21913904.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21914933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10956966 + 10956967.

It is an arithmetic number, because the mean of its divisors is an integer number (10956967).

Almost surely, 2^21913933 is an apocalyptic number.

It is an amenable number.

21913933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21913933 is an equidigital number, since it uses as much as digits as its factorization.

21913933 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374, while the sum is 31.

The square root of 21913933 is about 4681.2319959600. The cubic root of 21913933 is about 279.8380568655.

The spelling of 21913933 in words is "twenty-one million, nine hundred thirteen thousand, nine hundred thirty-three".