51581311 has 4 divisors (see below), whose sum is σ = 51601912. Its totient is φ = 51560712.

The previous prime is 51581297. The next prime is 51581317. The reversal of 51581311 is 11318515.

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 51581311 - 2⁵ = 51581279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51581317) 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, 5925 + ... + 11758.

It is an arithmetic number, because the mean of its divisors is an integer number (12900478).

Almost surely, 2^51581311 is an apocalyptic number.

51581311 is a deficient number, since it is larger than the sum of its proper divisors (20601).

51581311 is a wasteful number, since it uses less digits than its factorization.

51581311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20600.

The product of its digits is 600, while the sum is 25.

The square root of 51581311 is about 7182.0130186460. The cubic root of 51581311 is about 372.2466448304.

Adding to 51581311 its reverse (11318515), we get a palindrome (62899826).

The spelling of 51581311 in words is "fifty-one million, five hundred eighty-one thousand, three hundred eleven".