51613221 has 8 divisors (see below), whose sum is σ = 75073824. Its totient is φ = 31280720.

The previous prime is 51613213. The next prime is 51613231. The reversal of 51613221 is 12231615.

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

It is a cyclic number.

It is not a de Polignac number, because 51613221 - 2³ = 51613213 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51613231) 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, 781986 + ... + 782051.

It is an arithmetic number, because the mean of its divisors is an integer number (9384228).

Almost surely, 2^51613221 is an apocalyptic number.

It is an amenable number.

51613221 is a deficient number, since it is larger than the sum of its proper divisors (23460603).

51613221 is a wasteful number, since it uses less digits than its factorization.

51613221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1564051.

The product of its digits is 360, while the sum is 21.

The square root of 51613221 is about 7184.2341971848. The cubic root of 51613221 is about 372.3233905973.

Adding to 51613221 its reverse (12231615), we get a palindrome (63844836).

The spelling of 51613221 in words is "fifty-one million, six hundred thirteen thousand, two hundred twenty-one".