51561400 has 96 divisors (see below), whose sum is σ = 136598400. Its totient is φ = 17916800.

The previous prime is 51561379. The next prime is 51561427. The reversal of 51561400 is 416515.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50091 + ... + 51109.

It is an arithmetic number, because the mean of its divisors is an integer number (1422900).

Almost surely, 2^51561400 is an apocalyptic number.

51561400 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51561400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68299200).

51561400 is an abundant number, since it is smaller than the sum of its proper divisors (85037000).

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

51561400 is a wasteful number, since it uses less digits than its factorization.

51561400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1069 (or 1060 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 51561400 is about 7180.6267135954. The cubic root of 51561400 is about 372.1987414542.

Adding to 51561400 its reverse (416515), we get a palindrome (51977915).

It can be divided in two parts, 5156 and 1400, that added together give a palindrome (6556).

The spelling of 51561400 in words is "fifty-one million, five hundred sixty-one thousand, four hundred".