21772691 has 2 divisors, whose sum is σ = 21772692. Its totient is φ = 21772690.

The previous prime is 21772607. The next prime is 21772741. The reversal of 21772691 is 19627712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21772691 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21772601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10886345 + 10886346.

It is an arithmetic number, because the mean of its divisors is an integer number (10886346).

Almost surely, 2^21772691 is an apocalyptic number.

21772691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21772691 is an equidigital number, since it uses as much as digits as its factorization.

21772691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 35.

The square root of 21772691 is about 4666.1216229327. The cubic root of 21772691 is about 279.2355465985.

The spelling of 21772691 in words is "twenty-one million, seven hundred seventy-two thousand, six hundred ninety-one".