51781604 has 24 divisors (see below), whose sum is σ = 103826688. Its totient is φ = 22135680.

The previous prime is 51781603. The next prime is 51781621. The reversal of 51781604 is 40618715.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (51781603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9989 + ... + 14259.

It is an arithmetic number, because the mean of its divisors is an integer number (4326112).

Almost surely, 2^51781604 is an apocalyptic number.

It is an amenable number.

51781604 is an abundant number, since it is smaller than the sum of its proper divisors (52045084).

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

51781604 is a wasteful number, since it uses less digits than its factorization.

51781604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4715 (or 4713 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 51781604 is about 7195.9435795454. The cubic root of 51781604 is about 372.7278404332.

The spelling of 51781604 in words is "fifty-one million, seven hundred eighty-one thousand, six hundred four".