51991632 has 200 divisors, whose sum is σ = 187970112. Its totient is φ = 13478400.

The previous prime is 51991631. The next prime is 51991651. The reversal of 51991632 is 23619915.

51991632 is a `hidden beast` number, since 5 + 19 + 9 + 1 + 632 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51991631) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 99532 + ... + 100052.

Almost surely, 2^51991632 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51991632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93985056).

51991632 is an abundant number, since it is smaller than the sum of its proper divisors (135978480).

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

51991632 is a wasteful number, since it uses less digits than its factorization.

51991632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559 (or 544 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 51991632 is about 7210.5223111783. The cubic root of 51991632 is about 373.2310930350.

The spelling of 51991632 in words is "fifty-one million, nine hundred ninety-one thousand, six hundred thirty-two".