51090720 has 96 divisors (see below), whose sum is σ = 162171072. Its totient is φ = 13519872.

The previous prime is 51090709. The next prime is 51090727. The reversal of 51090720 is 2709015.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×51090720² = 5220523340236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (51090727) 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, 77914 + ... + 78566.

It is an arithmetic number, because the mean of its divisors is an integer number (1689282).

Almost surely, 2^51090720 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 51090720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81085536).

51090720 is an abundant number, since it is smaller than the sum of its proper divisors (111080352).

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

51090720 is a wasteful number, since it uses less digits than its factorization.

51090720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834 (or 826 counting only the distinct ones).

The product of its (nonzero) digits is 630, while the sum is 24.

The square root of 51090720 is about 7147.7772768882. Note that the first 3 decimals coincide. The cubic root of 51090720 is about 371.0627347456.

Adding to 51090720 its reverse (2709015), we get a palindrome (53799735).

The spelling of 51090720 in words is "fifty-one million, ninety thousand, seven hundred twenty".