51503101987 has 4 divisors (see below), whose sum is σ = 51879037176. Its totient is φ = 51127166800.

The previous prime is 51503101981. The next prime is 51503102009. The reversal of 51503101987 is 78910130515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78910130515 = 5 ⋅15782026103.

It is a cyclic number.

It is not a de Polignac number, because 51503101987 - 2³⁵ = 17143363619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51503101981) 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, 187967389 + ... + 187967662.

It is an arithmetic number, because the mean of its divisors is an integer number (12969759294).

Almost surely, 2^51503101987 is an apocalyptic number.

51503101987 is a deficient number, since it is larger than the sum of its proper divisors (375935189).

51503101987 is a wasteful number, since it uses less digits than its factorization.

51503101987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375935188.

The product of its (nonzero) digits is 37800, while the sum is 40.

The spelling of 51503101987 in words is "fifty-one billion, five hundred three million, one hundred one thousand, nine hundred eighty-seven".