51291009 has 32 divisors (see below), whose sum is σ = 94740480. Its totient is φ = 26643600.

The previous prime is 51291007. The next prime is 51291011. The reversal of 51291009 is 90019215.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (51291007) and next prime (51291011).

It is not a de Polignac number, because 51291009 - 2¹ = 51291007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (51291007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10257 + ... + 14414.

It is an arithmetic number, because the mean of its divisors is an integer number (2960640).

Almost surely, 2^51291009 is an apocalyptic number.

It is an amenable number.

51291009 is a deficient number, since it is larger than the sum of its proper divisors (43449471).

51291009 is a wasteful number, since it uses less digits than its factorization.

51291009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24698 (or 24692 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 51291009 is about 7161.7741517029. The cubic root of 51291009 is about 371.5469901862.

The spelling of 51291009 in words is "fifty-one million, two hundred ninety-one thousand, nine".