21973351 has 2 divisors, whose sum is σ = 21973352. Its totient is φ = 21973350.

The previous prime is 21973331. The next prime is 21973363. The reversal of 21973351 is 15337912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21973351 - 2⁵ = 21973319 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21973331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10986675 + 10986676.

It is an arithmetic number, because the mean of its divisors is an integer number (10986676).

Almost surely, 2^21973351 is an apocalyptic number.

21973351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21973351 is an equidigital number, since it uses as much as digits as its factorization.

21973351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5670, while the sum is 31.

The square root of 21973351 is about 4687.5741060809. The cubic root of 21973351 is about 280.0907486462.

The spelling of 21973351 in words is "twenty-one million, nine hundred seventy-three thousand, three hundred fifty-one".