51720205 has 16 divisors (see below), whose sum is σ = 66515904. Its totient is φ = 38467840.

The previous prime is 51720199. The next prime is 51720247. The reversal of 51720205 is 50202715.

It is not a de Polignac number, because 51720205 - 2³ = 51720197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3390 + ... + 10720.

It is an arithmetic number, because the mean of its divisors is an integer number (4157244).

Almost surely, 2^51720205 is an apocalyptic number.

It is an amenable number.

51720205 is a deficient number, since it is larger than the sum of its proper divisors (14795699).

51720205 is a wasteful number, since it uses less digits than its factorization.

51720205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7436.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 51720205 is about 7191.6760911487. The cubic root of 51720205 is about 372.5804639774.

The spelling of 51720205 in words is "fifty-one million, seven hundred twenty thousand, two hundred five".