51081531 has 16 divisors (see below), whose sum is σ = 70738080. Its totient is φ = 32762880.

The previous prime is 51081529. The next prime is 51081533. The reversal of 51081531 is 13518015.

It is an interprime number because it is at equal distance from previous prime (51081529) and next prime (51081533).

It is not a de Polignac number, because 51081531 - 2¹ = 51081529 is a prime.

It is a super-2 number, since 2×51081531² = 5218645618607922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51081533) 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, 6135 + ... + 11823.

It is an arithmetic number, because the mean of its divisors is an integer number (4421130).

Almost surely, 2^51081531 is an apocalyptic number.

51081531 is a deficient number, since it is larger than the sum of its proper divisors (19656549).

51081531 is a wasteful number, since it uses less digits than its factorization.

51081531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5806.

The product of its (nonzero) digits is 600, while the sum is 24.

The square root of 51081531 is about 7147.1344607472. The cubic root of 51081531 is about 371.0404873923.

Adding to 51081531 its reverse (13518015), we get a palindrome (64599546).

The spelling of 51081531 in words is "fifty-one million, eighty-one thousand, five hundred thirty-one".