20515124551 has 4 divisors (see below), whose sum is σ = 21407086512. Its totient is φ = 19623162592.

The previous prime is 20515124533. The next prime is 20515124569. The reversal of 20515124551 is 15542151502.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20515124533) and next prime (20515124569).

It is a cyclic number.

It is not a de Polignac number, because 20515124551 - 2³³ = 11925189959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20515124251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 445980946 + ... + 445980991.

It is an arithmetic number, because the mean of its divisors is an integer number (5351771628).

Almost surely, 2^20515124551 is an apocalyptic number.

20515124551 is a deficient number, since it is larger than the sum of its proper divisors (891961961).

20515124551 is an equidigital number, since it uses as much as digits as its factorization.

20515124551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891961960.

The product of its (nonzero) digits is 10000, while the sum is 31.

The spelling of 20515124551 in words is "twenty billion, five hundred fifteen million, one hundred twenty-four thousand, five hundred fifty-one".