20215451 has 2 divisors, whose sum is σ = 20215452. Its totient is φ = 20215450.

The previous prime is 20215417. The next prime is 20215457. The reversal of 20215451 is 15451202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20215451 - 2¹⁰ = 20214427 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20215457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10107725 + 10107726.

It is an arithmetic number, because the mean of its divisors is an integer number (10107726).

Almost surely, 2^20215451 is an apocalyptic number.

20215451 is a deficient number, since it is larger than the sum of its proper divisors (1).

20215451 is an equidigital number, since it uses as much as digits as its factorization.

20215451 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 20215451 is about 4496.1595834668. The cubic root of 20215451 is about 272.4129890815.

Adding to 20215451 its reverse (15451202), we get a palindrome (35666653).

The spelling of 20215451 in words is "twenty million, two hundred fifteen thousand, four hundred fifty-one".