20515879 has 2 divisors, whose sum is σ = 20515880. Its totient is φ = 20515878.

The previous prime is 20515853. The next prime is 20515903. The reversal of 20515879 is 97851502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20515879 - 2⁹ = 20515367 is a prime.

It is a super-2 number, since 2×20515879² = 841802582285282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20515819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10257939 + 10257940.

It is an arithmetic number, because the mean of its divisors is an integer number (10257940).

Almost surely, 2^20515879 is an apocalyptic number.

20515879 is a deficient number, since it is larger than the sum of its proper divisors (1).

20515879 is an equidigital number, since it uses as much as digits as its factorization.

20515879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 20515879 is about 4529.4457718357. The cubic root of 20515879 is about 273.7558296820.

The spelling of 20515879 in words is "twenty million, five hundred fifteen thousand, eight hundred seventy-nine".