51390861 has 16 divisors (see below), whose sum is σ = 69806016. Its totient is φ = 33623936.

The previous prime is 51390851. The next prime is 51390883. The reversal of 51390861 is 16809315.

It is a cyclic number.

It is not a de Polignac number, because 51390861 - 2⁷ = 51390733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51390811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42481 + ... + 43673.

It is an arithmetic number, because the mean of its divisors is an integer number (4362876).

Almost surely, 2^51390861 is an apocalyptic number.

It is an amenable number.

51390861 is a deficient number, since it is larger than the sum of its proper divisors (18415155).

51390861 is a wasteful number, since it uses less digits than its factorization.

51390861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 51390861 is about 7168.7419398385. The cubic root of 51390861 is about 371.7879398957.

The spelling of 51390861 in words is "fifty-one million, three hundred ninety thousand, eight hundred sixty-one".