20515051 has 2 divisors, whose sum is σ = 20515052. Its totient is φ = 20515050.

The previous prime is 20515013. The next prime is 20515069. The reversal of 20515051 is 15051502.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20515051 is a prime.

It is not a weakly prime, because it can be changed into another prime (20515351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10257525 + 10257526.

It is an arithmetic number, because the mean of its divisors is an integer number (10257526).

Almost surely, 2^20515051 is an apocalyptic number.

20515051 is a deficient number, since it is larger than the sum of its proper divisors (1).

20515051 is an equidigital number, since it uses as much as digits as its factorization.

20515051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 250, while the sum is 19.

The square root of 20515051 is about 4529.3543690023. The cubic root of 20515051 is about 273.7521467969.

Adding to 20515051 its reverse (15051502), we get a palindrome (35566553).

The spelling of 20515051 in words is "twenty million, five hundred fifteen thousand, fifty-one".