51147720 has 128 divisors (see below), whose sum is σ = 183657600. Its totient is φ = 12586752.

The previous prime is 51147709. The next prime is 51147721. The reversal of 51147720 is 2774115.

It is a super-2 number, since 2×51147720² = 5232178522396800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (51147721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12219 + ... + 15861.

It is an arithmetic number, because the mean of its divisors is an integer number (1434825).

Almost surely, 2^51147720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51147720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91828800).

51147720 is an abundant number, since it is smaller than the sum of its proper divisors (132509880).

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

51147720 is a wasteful number, since it uses less digits than its factorization.

51147720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3676 (or 3666 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 51147720 is about 7151.7634189059. The cubic root of 51147720 is about 371.2006770511.

The spelling of 51147720 in words is "fifty-one million, one hundred forty-seven thousand, seven hundred twenty".