51132991 has 16 divisors (see below), whose sum is σ = 66636864. Its totient is φ = 38075904.

The previous prime is 51132989. The next prime is 51132997. The reversal of 51132991 is 19923115.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 51132991 - 2¹ = 51132989 is a prime.

It is a super-2 number, since 2×51132991² = 5229165537212162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51132997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14980 + ... + 18073.

It is an arithmetic number, because the mean of its divisors is an integer number (4164804).

Almost surely, 2^51132991 is an apocalyptic number.

51132991 is a deficient number, since it is larger than the sum of its proper divisors (15503873).

51132991 is a wasteful number, since it uses less digits than its factorization.

51132991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33090.

The product of its digits is 2430, while the sum is 31.

The square root of 51132991 is about 7150.7335987296. The cubic root of 51132991 is about 371.1650420989.

The spelling of 51132991 in words is "fifty-one million, one hundred thirty-two thousand, nine hundred ninety-one".