51621393 has 8 divisors (see below), whose sum is σ = 68863648. Its totient is φ = 34396704.

The previous prime is 51621359. The next prime is 51621431. The reversal of 51621393 is 39312615.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51621393 - 2⁶ = 51621329 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51621393.

It is not an unprimeable number, because it can be changed into a prime (51621593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5946 + ... + 11772.

It is an arithmetic number, because the mean of its divisors is an integer number (8607956).

Almost surely, 2^51621393 is an apocalyptic number.

It is an amenable number.

51621393 is a deficient number, since it is larger than the sum of its proper divisors (17242255).

51621393 is a wasteful number, since it uses less digits than its factorization.

51621393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8783.

The product of its digits is 4860, while the sum is 30.

The square root of 51621393 is about 7184.8029200529. The cubic root of 51621393 is about 372.3430397371.

It can be divided in two parts, 5162 and 1393, that added together give a triangular number (6555 = T₁₁₄).

The spelling of 51621393 in words is "fifty-one million, six hundred twenty-one thousand, three hundred ninety-three".