51139705 has 8 divisors (see below), whose sum is σ = 61417800. Its totient is φ = 40878336.

The previous prime is 51139681. The next prime is 51139709. The reversal of 51139705 is 50793115.

It can be written as a sum of positive squares in 4 ways, for example, as 1352569 + 49787136 = 1163^2 + 7056^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 51139705 - 2²³ = 42751097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51139709) 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, 4011 + ... + 10879.

It is an arithmetic number, because the mean of its divisors is an integer number (7677225).

Almost surely, 2^51139705 is an apocalyptic number.

It is an amenable number.

51139705 is a deficient number, since it is larger than the sum of its proper divisors (10278095).

51139705 is a wasteful number, since it uses less digits than its factorization.

51139705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8363.

The product of its (nonzero) digits is 4725, while the sum is 31.

The square root of 51139705 is about 7151.2030456420. The cubic root of 51139705 is about 371.1812866212.

The spelling of 51139705 in words is "fifty-one million, one hundred thirty-nine thousand, seven hundred five".