51309961 has 16 divisors (see below), whose sum is σ = 56592000. Its totient is φ = 46303488.

The previous prime is 51309959. The next prime is 51309971. The reversal of 51309961 is 16990315.

It is not a de Polignac number, because 51309961 - 2¹ = 51309959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51309911) 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, 97846 + ... + 98368.

It is an arithmetic number, because the mean of its divisors is an integer number (3537000).

Almost surely, 2^51309961 is an apocalyptic number.

It is an amenable number.

51309961 is a deficient number, since it is larger than the sum of its proper divisors (5282039).

51309961 is a wasteful number, since it uses less digits than its factorization.

51309961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 51309961 is about 7163.0971653329. The cubic root of 51309961 is about 371.5927466881.

The spelling of 51309961 in words is "fifty-one million, three hundred nine thousand, nine hundred sixty-one".