51919209 has 6 divisors (see below), whose sum is σ = 74994426. Its totient is φ = 34612800.

The previous prime is 51919201. The next prime is 51919223. The reversal of 51919209 is 90291915.

It can be written as a sum of positive squares in only one way, i.e., 38937600 + 12981609 = 6240^2 + 3603^2 .

It is not a de Polignac number, because 51919209 - 2³ = 51919201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51919201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2884392 + ... + 2884409.

It is an arithmetic number, because the mean of its divisors is an integer number (12499071).

Almost surely, 2^51919209 is an apocalyptic number.

It is an amenable number.

51919209 is a deficient number, since it is larger than the sum of its proper divisors (23075217).

51919209 is a wasteful number, since it uses less digits than its factorization.

51919209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5768807 (or 5768804 counting only the distinct ones).

The product of its (nonzero) digits is 7290, while the sum is 36.

The square root of 51919209 is about 7205.4985254318. The cubic root of 51919209 is about 373.0577120820.

It can be divided in two parts, 5191 and 9209, that added together give a square (14400 = 120²).

The spelling of 51919209 in words is "fifty-one million, nine hundred nineteen thousand, two hundred nine".