51621331 has 4 divisors (see below), whose sum is σ = 52348464. Its totient is φ = 50894200.

The previous prime is 51621329. The next prime is 51621341. The reversal of 51621331 is 13312615.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 51621331 - 2¹ = 51621329 is a prime.

It is a super-2 number, since 2×51621331² = 5329523628423122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51621341) 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, 363460 + ... + 363601.

It is an arithmetic number, because the mean of its divisors is an integer number (13087116).

Almost surely, 2^51621331 is an apocalyptic number.

51621331 is a deficient number, since it is larger than the sum of its proper divisors (727133).

51621331 is an equidigital number, since it uses as much as digits as its factorization.

51621331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727132.

The product of its digits is 540, while the sum is 22.

The square root of 51621331 is about 7184.7986053890. The cubic root of 51621331 is about 372.3428906692.

Adding to 51621331 its reverse (13312615), we get a palindrome (64933946).

The spelling of 51621331 in words is "fifty-one million, six hundred twenty-one thousand, three hundred thirty-one".