51216353491 has 8 divisors (see below), whose sum is σ = 51568766480. Its totient is φ = 50865146208.

The previous prime is 51216353483. The next prime is 51216353537. The reversal of 51216353491 is 19435361215.

It is a happy number.

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 51216353491 - 2³ = 51216353483 is a prime.

It is a super-2 number, since 2×51216353491² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51216353401) 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, 216096 + ... + 386173.

It is an arithmetic number, because the mean of its divisors is an integer number (6446095810).

Almost surely, 2^51216353491 is an apocalyptic number.

51216353491 is a deficient number, since it is larger than the sum of its proper divisors (352412989).

51216353491 is a wasteful number, since it uses less digits than its factorization.

51216353491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602853.

The product of its digits is 97200, while the sum is 40.

The spelling of 51216353491 in words is "fifty-one billion, two hundred sixteen million, three hundred fifty-three thousand, four hundred ninety-one".