51380781 has 8 divisors (see below), whose sum is σ = 71486400. Its totient is φ = 32764512.

The previous prime is 51380737. The next prime is 51380789. The reversal of 51380781 is 18708315.

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

It is not a de Polignac number, because 51380781 - 2⁶ = 51380717 is a prime.

It is a super-2 number, since 2×51380781² = 5279969312339922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51380789) 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, 372256 + ... + 372393.

It is an arithmetic number, because the mean of its divisors is an integer number (8935800).

Almost surely, 2^51380781 is an apocalyptic number.

It is an amenable number.

51380781 is a deficient number, since it is larger than the sum of its proper divisors (20105619).

51380781 is a wasteful number, since it uses less digits than its factorization.

51380781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744675.

The product of its (nonzero) digits is 6720, while the sum is 33.

The square root of 51380781 is about 7168.0388531313. The cubic root of 51380781 is about 371.7636303368.

The spelling of 51380781 in words is "fifty-one million, three hundred eighty thousand, seven hundred eighty-one".