21790597 has 2 divisors, whose sum is σ = 21790598. Its totient is φ = 21790596.

The previous prime is 21790567. The next prime is 21790609. The reversal of 21790597 is 79509712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15610401 + 6180196 = 3951^2 + 2486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21790597 - 2¹¹ = 21788549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21790507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10895298 + 10895299.

It is an arithmetic number, because the mean of its divisors is an integer number (10895299).

Almost surely, 2^21790597 is an apocalyptic number.

It is an amenable number.

21790597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21790597 is an equidigital number, since it uses as much as digits as its factorization.

21790597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39690, while the sum is 40.

The square root of 21790597 is about 4668.0399526996. The cubic root of 21790597 is about 279.3120739886.

The spelling of 21790597 in words is "twenty-one million, seven hundred ninety thousand, five hundred ninety-seven".