51221610 has 96 divisors (see below), whose sum is σ = 150059520. Its totient is φ = 12009600.

The previous prime is 51221593. The next prime is 51221623. The reversal of 51221610 is 1612215.

51221610 is a `hidden beast` number, since 51 + 2 + 2 + 1 + 610 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 29856 + ... + 31524.

It is an arithmetic number, because the mean of its divisors is an integer number (1563120).

Almost surely, 2^51221610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51221610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75029760).

51221610 is an abundant number, since it is smaller than the sum of its proper divisors (98837910).

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

51221610 is a wasteful number, since it uses less digits than its factorization.

51221610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1724 (or 1721 counting only the distinct ones).

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

The square root of 51221610 is about 7156.9274133527. The cubic root of 51221610 is about 371.3793413901.

Adding to 51221610 its reverse (1612215), we get a palindrome (52833825).

It can be divided in two parts, 512 and 21610, that added together give a palindrome (22122).

The spelling of 51221610 in words is "fifty-one million, two hundred twenty-one thousand, six hundred ten".