51971766 has 128 divisors (see below), whose sum is σ = 139124736. Its totient is φ = 12545280.

The previous prime is 51971753. The next prime is 51971767. The reversal of 51971766 is 66717915.

It is a super-2 number, since 2×51971766² = 5402128922317512, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51971767) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 711906 + ... + 711978.

It is an arithmetic number, because the mean of its divisors is an integer number (1086912).

Almost surely, 2^51971766 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51971766, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69562368).

51971766 is an abundant number, since it is smaller than the sum of its proper divisors (87152970).

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

51971766 is a wasteful number, since it uses less digits than its factorization.

51971766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186.

The product of its digits is 79380, while the sum is 42.

The square root of 51971766 is about 7209.1446094526. The cubic root of 51971766 is about 373.1835497850.

The spelling of 51971766 in words is "fifty-one million, nine hundred seventy-one thousand, seven hundred sixty-six".