51620009 has 4 divisors (see below), whose sum is σ = 58994304. Its totient is φ = 44245716.

The previous prime is 51619999. The next prime is 51620011. The reversal of 51620009 is 90002615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51620009 - 2⁸ = 51619753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51620099) 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, 3687137 + ... + 3687150.

It is an arithmetic number, because the mean of its divisors is an integer number (14748576).

Almost surely, 2^51620009 is an apocalyptic number.

It is an amenable number.

51620009 is a deficient number, since it is larger than the sum of its proper divisors (7374295).

51620009 is an equidigital number, since it uses as much as digits as its factorization.

51620009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7374294.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 51620009 is about 7184.7066050048. The cubic root of 51620009 is about 372.3397121285.

The spelling of 51620009 in words is "fifty-one million, six hundred twenty thousand, nine".