51206987 has 4 divisors (see below), whose sum is σ = 55146000. Its totient is φ = 47267976.

The previous prime is 51206971. The next prime is 51206989. The reversal of 51206987 is 78960215.

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

It is a cyclic number.

It is not a de Polignac number, because 51206987 - 2⁴ = 51206971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51206987.

It is not an unprimeable number, because it can be changed into a prime (51206989) 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, 1969487 + ... + 1969512.

It is an arithmetic number, because the mean of its divisors is an integer number (13786500).

Almost surely, 2^51206987 is an apocalyptic number.

51206987 is a deficient number, since it is larger than the sum of its proper divisors (3939013).

51206987 is a wasteful number, since it uses less digits than its factorization.

51206987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3939012.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 51206987 is about 7155.9057428113. The cubic root of 51206987 is about 371.3439969526.

The spelling of 51206987 in words is "fifty-one million, two hundred six thousand, nine hundred eighty-seven".