51987566 has 4 divisors (see below), whose sum is σ = 77981352. Its totient is φ = 25993782.

The previous prime is 51987563. The next prime is 51987569. The reversal of 51987566 is 66578915.

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 (51987563) and next prime (51987569).

It is a self number, because there is not a number n which added to its sum of digits gives 51987566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51987563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12996890 + ... + 12996893.

It is an arithmetic number, because the mean of its divisors is an integer number (19495338).

Almost surely, 2^51987566 is an apocalyptic number.

51987566 is a deficient number, since it is larger than the sum of its proper divisors (25993786).

51987566 is a wasteful number, since it uses less digits than its factorization.

51987566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25993785.

The product of its digits is 453600, while the sum is 47.

The square root of 51987566 is about 7210.2403566039. The cubic root of 51987566 is about 373.2213632822.

The spelling of 51987566 in words is "fifty-one million, nine hundred eighty-seven thousand, five hundred sixty-six".