51081651 has 32 divisors (see below), whose sum is σ = 80942400. Its totient is φ = 31726080.

The previous prime is 51081647. The next prime is 51081661. The reversal of 51081651 is 15618015.

51081651 is a `hidden beast` number, since 5 + 1 + 0 + 8 + 1 + 651 = 666.

It is not a de Polignac number, because 51081651 - 2² = 51081647 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 (51081631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49521 + ... + 50541.

It is an arithmetic number, because the mean of its divisors is an integer number (2529450).

Almost surely, 2^51081651 is an apocalyptic number.

51081651 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

51081651 is a deficient number, since it is larger than the sum of its proper divisors (29860749).

51081651 is a wasteful number, since it uses less digits than its factorization.

51081651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156 (or 1150 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 27.

The square root of 51081651 is about 7147.1428557151. The cubic root of 51081651 is about 371.0407779397.

Adding to 51081651 its reverse (15618015), we get a palindrome (66699666).

The spelling of 51081651 in words is "fifty-one million, eighty-one thousand, six hundred fifty-one".