51609940 has 12 divisors (see below), whose sum is σ = 108380916. Its totient is φ = 20643968.

The previous prime is 51609923. The next prime is 51609973. The reversal of 51609940 is 4990615.

It can be written as a sum of positive squares in 2 ways, for example, as 32285124 + 19324816 = 5682^2 + 4396^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51609896 and 51609905.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1290229 + ... + 1290268.

It is an arithmetic number, because the mean of its divisors is an integer number (9031743).

Almost surely, 2^51609940 is an apocalyptic number.

It is an amenable number.

51609940 is an abundant number, since it is smaller than the sum of its proper divisors (56770976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51609940 is a wasteful number, since it uses less digits than its factorization.

51609940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2580506 (or 2580504 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 51609940 is about 7184.0058463228. The cubic root of 51609940 is about 372.3155010236.

The spelling of 51609940 in words is "fifty-one million, six hundred nine thousand, nine hundred forty".