21992351 has 2 divisors, whose sum is σ = 21992352. Its totient is φ = 21992350.

The previous prime is 21992317. The next prime is 21992357. The reversal of 21992351 is 15329912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21992351 - 2²² = 17798047 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 (21992357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10996175 + 10996176.

It is an arithmetic number, because the mean of its divisors is an integer number (10996176).

Almost surely, 2^21992351 is an apocalyptic number.

21992351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21992351 is an equidigital number, since it uses as much as digits as its factorization.

21992351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 32.

The square root of 21992351 is about 4689.6003027977. The cubic root of 21992351 is about 280.1714553636.

The spelling of 21992351 in words is "twenty-one million, nine hundred ninety-two thousand, three hundred fifty-one".