51429987 has 24 divisors (see below), whose sum is σ = 85096544. Its totient is φ = 29320704.

The previous prime is 51429977. The next prime is 51429991. The reversal of 51429987 is 78992415.

It is not a de Polignac number, because 51429987 - 2¹¹ = 51427939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51429967) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41793 + ... + 43005.

Almost surely, 2^51429987 is an apocalyptic number.

51429987 is a deficient number, since it is larger than the sum of its proper divisors (33666557).

51429987 is a wasteful number, since it uses less digits than its factorization.

51429987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1899 (or 1896 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 51429987 is about 7171.4703513296. The cubic root of 51429987 is about 371.8822685019.

It can be divided in two parts, 5142 and 9987, that added together give a square (15129 = 123²).

The spelling of 51429987 in words is "fifty-one million, four hundred twenty-nine thousand, nine hundred eighty-seven".