21292091 has 2 divisors, whose sum is σ = 21292092. Its totient is φ = 21292090.

The previous prime is 21292067. The next prime is 21292099. The reversal of 21292091 is 19029212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21292091 - 2¹⁴ = 21275707 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21292091.

It is not a weakly prime, because it can be changed into another prime (21292099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646045 + 10646046.

It is an arithmetic number, because the mean of its divisors is an integer number (10646046).

Almost surely, 2^21292091 is an apocalyptic number.

21292091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21292091 is an equidigital number, since it uses as much as digits as its factorization.

21292091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21292091 is about 4614.3353800954. The cubic root of 21292091 is about 277.1656704646.

The spelling of 21292091 in words is "twenty-one million, two hundred ninety-two thousand, ninety-one".