51561100 has 18 divisors (see below), whose sum is σ = 111887804. Its totient is φ = 20624400.

The previous prime is 51561061. The next prime is 51561127. The reversal of 51561100 is 116515.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 257706 + ... + 257905.

Almost surely, 2^51561100 is an apocalyptic number.

51561100 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51561100 is an abundant number, since it is smaller than the sum of its proper divisors (60326704).

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

51561100 is a wasteful number, since it uses less digits than its factorization.

51561100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515625 (or 515618 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 19.

The square root of 51561100 is about 7180.6058240235. The cubic root of 51561100 is about 372.1980195974.

Adding to 51561100 its reverse (116515), we get a palindrome (51677615).

The spelling of 51561100 in words is "fifty-one million, five hundred sixty-one thousand, one hundred".