21764051 has 2 divisors, whose sum is σ = 21764052. Its totient is φ = 21764050.

The previous prime is 21764027. The next prime is 21764053. The reversal of 21764051 is 15046712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21764051 - 2¹⁴ = 21747667 is a prime.

Together with 21764053, it forms a pair of twin primes.

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 21764051.

It is not a weakly prime, because it can be changed into another prime (21764053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882025 + 10882026.

It is an arithmetic number, because the mean of its divisors is an integer number (10882026).

Almost surely, 2^21764051 is an apocalyptic number.

21764051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764051 is an equidigital number, since it uses as much as digits as its factorization.

21764051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21764051 is about 4665.1957086493. The cubic root of 21764051 is about 279.1986056079.

The spelling of 21764051 in words is "twenty-one million, seven hundred sixty-four thousand, fifty-one".