51561908 has 6 divisors (see below), whose sum is σ = 90233346. Its totient is φ = 25780952.

The previous prime is 51561907. The next prime is 51561919. The reversal of 51561908 is 80916515.

It can be written as a sum of positive squares in only one way, i.e., 46076944 + 5484964 = 6788^2 + 2342^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51561907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6445235 + ... + 6445242.

It is an arithmetic number, because the mean of its divisors is an integer number (15038891).

Almost surely, 2^51561908 is an apocalyptic number.

It is an amenable number.

51561908 is a deficient number, since it is larger than the sum of its proper divisors (38671438).

51561908 is a wasteful number, since it uses less digits than its factorization.

51561908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12890481 (or 12890479 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 35.

The square root of 51561908 is about 7180.6620864653. The cubic root of 51561908 is about 372.1999637920.

The spelling of 51561908 in words is "fifty-one million, five hundred sixty-one thousand, nine hundred eight".