51951681 has 24 divisors (see below), whose sum is σ = 79560000. Its totient is φ = 32575392.

The previous prime is 51951661. The next prime is 51951709. The reversal of 51951681 is 18615915.

It is not a de Polignac number, because 51951681 - 2¹⁴ = 51935297 is a prime.

It is a super-2 number, since 2×51951681² = 5397954317451522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51951661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24460 + ... + 26498.

It is an arithmetic number, because the mean of its divisors is an integer number (3315000).

Almost surely, 2^51951681 is an apocalyptic number.

It is an amenable number.

51951681 is a deficient number, since it is larger than the sum of its proper divisors (27608319).

51951681 is a wasteful number, since it uses less digits than its factorization.

51951681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2213 (or 2210 counting only the distinct ones).

The product of its digits is 10800, while the sum is 36.

The square root of 51951681 is about 7207.7514524295. The cubic root of 51951681 is about 373.1354701068.

The spelling of 51951681 in words is "fifty-one million, nine hundred fifty-one thousand, six hundred eighty-one".