51990619 has 4 divisors (see below), whose sum is σ = 52617096. Its totient is φ = 51364144.

The previous prime is 51990613. The next prime is 51990667. The reversal of 51990619 is 91609915.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51990619 is a prime.

It is a super-2 number, since 2×51990619² = 5406048928006322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51990613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 313114 + ... + 313279.

It is an arithmetic number, because the mean of its divisors is an integer number (13154274).

Almost surely, 2^51990619 is an apocalyptic number.

51990619 is a deficient number, since it is larger than the sum of its proper divisors (626477).

51990619 is an equidigital number, since it uses as much as digits as its factorization.

51990619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626476.

The product of its (nonzero) digits is 21870, while the sum is 40.

The square root of 51990619 is about 7210.4520662716. The cubic root of 51990619 is about 373.2286690196.

The spelling of 51990619 in words is "fifty-one million, nine hundred ninety thousand, six hundred nineteen".