51506490 has 32 divisors (see below), whose sum is σ = 141275520. Its totient is φ = 11772864.

The previous prime is 51506471. The next prime is 51506491. The reversal of 51506490 is 9460515.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51506491) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122425 + ... + 122844.

It is an arithmetic number, because the mean of its divisors is an integer number (4414860).

Almost surely, 2^51506490 is an apocalyptic number.

51506490 is an abundant number, since it is smaller than the sum of its proper divisors (89769030).

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

51506490 is a wasteful number, since it uses less digits than its factorization.

51506490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245286.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 51506490 is about 7176.8022126850. The cubic root of 51506490 is about 372.0665709281.

The spelling of 51506490 in words is "fifty-one million, five hundred six thousand, four hundred ninety".