51402809 has 8 divisors (see below), whose sum is σ = 54996480. Its totient is φ = 47898000.

The previous prime is 51402803. The next prime is 51402821. The reversal of 51402809 is 90820415.

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 51402809 - 2⁸ = 51402553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51402803) 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, 21017 + ... + 23334.

It is an arithmetic number, because the mean of its divisors is an integer number (6874560).

Almost surely, 2^51402809 is an apocalyptic number.

It is an amenable number.

51402809 is a deficient number, since it is larger than the sum of its proper divisors (3593671).

51402809 is a wasteful number, since it uses less digits than its factorization.

51402809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44431.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 51402809 is about 7169.5752314904. The cubic root of 51402809 is about 371.8167503237.

The spelling of 51402809 in words is "fifty-one million, four hundred two thousand, eight hundred nine".