51721250 has 80 divisors (see below), whose sum is σ = 116062848. Its totient is φ = 16896000.

The previous prime is 51721231. The next prime is 51721261. The reversal of 51721250 is 5212715.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 201122 + ... + 201378.

Almost surely, 2^51721250 is an apocalyptic number.

51721250 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

51721250 is an abundant number, since it is smaller than the sum of its proper divisors (64341598).

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

51721250 is a wasteful number, since it uses less digits than its factorization.

51721250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 51721250 is about 7191.7487442207. The cubic root of 51721250 is about 372.5829732737.

Adding to 51721250 its reverse (5212715), we get a palindrome (56933965).

The spelling of 51721250 in words is "fifty-one million, seven hundred twenty-one thousand, two hundred fifty".