51215700 has 72 divisors (see below), whose sum is σ = 150129280. Its totient is φ = 13478400.

The previous prime is 51215699. The next prime is 51215729. The reversal of 51215700 is 751215.

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, 22620 + ... + 24780.

Almost surely, 2^51215700 is an apocalyptic number.

51215700 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 51215700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75064640).

51215700 is an abundant number, since it is smaller than the sum of its proper divisors (98913580).

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

51215700 is a wasteful number, since it uses less digits than its factorization.

51215700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2257 (or 2250 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 21.

The square root of 51215700 is about 7156.5145147621. The cubic root of 51215700 is about 371.3650574689.

Adding to 51215700 its reverse (751215), we get a palindrome (51966915).

It can be divided in two parts, 51215 and 700, that added together give a palindrome (51915).

The spelling of 51215700 in words is "fifty-one million, two hundred fifteen thousand, seven hundred".