21774451 has 2 divisors, whose sum is σ = 21774452. Its totient is φ = 21774450.

The previous prime is 21774449. The next prime is 21774479. The reversal of 21774451 is 15447712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21774451 - 2¹ = 21774449 is a prime.

Together with 21774449, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21774421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887225 + 10887226.

It is an arithmetic number, because the mean of its divisors is an integer number (10887226).

Almost surely, 2^21774451 is an apocalyptic number.

21774451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21774451 is an equidigital number, since it uses as much as digits as its factorization.

21774451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7840, while the sum is 31.

The square root of 21774451 is about 4666.3102125770. The cubic root of 21774451 is about 279.2430704169.

The spelling of 21774451 in words is "twenty-one million, seven hundred seventy-four thousand, four hundred fifty-one".