51405705 has 64 divisors (see below), whose sum is σ = 104267520. Its totient is φ = 23804928.

The previous prime is 51405701. The next prime is 51405709. The reversal of 51405705 is 50750415.

51405705 is a `hidden beast` number, since 51 + 40 + 570 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (51405701) and next prime (51405709).

It is not a de Polignac number, because 51405705 - 2² = 51405701 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51405701) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28974 + ... + 30696.

It is an arithmetic number, because the mean of its divisors is an integer number (1629180).

Almost surely, 2^51405705 is an apocalyptic number.

It is an amenable number.

51405705 is an abundant number, since it is smaller than the sum of its proper divisors (52861815).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51405705 is a wasteful number, since it uses less digits than its factorization.

51405705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1767 (or 1761 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 27.

The square root of 51405705 is about 7169.7771931909. Note that the first 3 decimals coincide. The cubic root of 51405705 is about 371.8237328285.

The spelling of 51405705 in words is "fifty-one million, four hundred five thousand, seven hundred five".