51121620 has 72 divisors (see below), whose sum is σ = 169172640. Its totient is φ = 12392640.

The previous prime is 51121613. The next prime is 51121649. The reversal of 51121620 is 2612115.

It is a super-2 number, since 2×51121620² = 5226840062848800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 51121593 and 51121602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10930 + ... + 14889.

It is an arithmetic number, because the mean of its divisors is an integer number (2349620).

Almost surely, 2^51121620 is an apocalyptic number.

It is an amenable number.

51121620 is an abundant number, since it is smaller than the sum of its proper divisors (118051020).

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

51121620 is a wasteful number, since it uses less digits than its factorization.

51121620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25845 (or 25840 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 51121620 is about 7149.9384612736. The cubic root of 51121620 is about 371.1375267218.

Adding to 51121620 its reverse (2612115), we get a palindrome (53733735).

The spelling of 51121620 in words is "fifty-one million, one hundred twenty-one thousand, six hundred twenty".