51908781 has 8 divisors (see below), whose sum is σ = 70045920. Its totient is φ = 34188752.

The previous prime is 51908761. The next prime is 51908789. The reversal of 51908781 is 18780915.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51908781 is a prime.

It is a super-2 number, since 2×51908781² = 5389043089811922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51908789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 103986 + ... + 104483.

It is an arithmetic number, because the mean of its divisors is an integer number (8755740).

Almost surely, 2^51908781 is an apocalyptic number.

It is an amenable number.

51908781 is a deficient number, since it is larger than the sum of its proper divisors (18137139).

51908781 is a wasteful number, since it uses less digits than its factorization.

51908781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208555.

The product of its (nonzero) digits is 20160, while the sum is 39.

The square root of 51908781 is about 7204.7748750395. The cubic root of 51908781 is about 373.0327341315.

The spelling of 51908781 in words is "fifty-one million, nine hundred eight thousand, seven hundred eighty-one".