51021566 has 4 divisors (see below), whose sum is σ = 76532352. Its totient is φ = 25510782.

The previous prime is 51021533. The next prime is 51021569. The reversal of 51021566 is 66512015.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12755390 + ... + 12755393.

It is an arithmetic number, because the mean of its divisors is an integer number (19133088).

Almost surely, 2^51021566 is an apocalyptic number.

51021566 is a deficient number, since it is larger than the sum of its proper divisors (25510786).

51021566 is a wasteful number, since it uses less digits than its factorization.

51021566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25510785.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 51021566 is about 7142.9381909688. The cubic root of 51021566 is about 370.8952414535.

The spelling of 51021566 in words is "fifty-one million, twenty-one thousand, five hundred sixty-six".