21790451 has 2 divisors, whose sum is σ = 21790452. Its totient is φ = 21790450.

The previous prime is 21790441. The next prime is 21790459. The reversal of 21790451 is 15409712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21790451 - 2⁶ = 21790387 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21790459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10895225 + 10895226.

It is an arithmetic number, because the mean of its divisors is an integer number (10895226).

Almost surely, 2^21790451 is an apocalyptic number.

21790451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21790451 is an equidigital number, since it uses as much as digits as its factorization.

21790451 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21790451 is about 4668.0243144183. The cubic root of 21790451 is about 279.3114501774.

The spelling of 21790451 in words is "twenty-one million, seven hundred ninety thousand, four hundred fifty-one".