51329781 has 40 divisors (see below), whose sum is σ = 79685760. Its totient is φ = 32908032.

The previous prime is 51329743. The next prime is 51329807. The reversal of 51329781 is 18792315.

It is not a de Polignac number, because 51329781 - 2¹⁴ = 51313397 is a prime.

It is a super-2 number, since 2×51329781² = 5269492835015922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51329711) 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, 369210 + ... + 369348.

It is an arithmetic number, because the mean of its divisors is an integer number (1992144).

Almost surely, 2^51329781 is an apocalyptic number.

It is an amenable number.

51329781 is a deficient number, since it is larger than the sum of its proper divisors (28355979).

51329781 is a wasteful number, since it uses less digits than its factorization.

51329781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295 (or 286 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 51329781 is about 7164.4805115235. The cubic root of 51329781 is about 371.6405867825.

The spelling of 51329781 in words is "fifty-one million, three hundred twenty-nine thousand, seven hundred eighty-one".