51231551 has 8 divisors (see below), whose sum is σ = 59796480. Its totient is φ = 42978168.

The previous prime is 51231547. The next prime is 51231553. The reversal of 51231551 is 15513215.

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 51231551 - 2² = 51231547 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 (51231553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77531 + ... + 78188.

It is an arithmetic number, because the mean of its divisors is an integer number (7474560).

Almost surely, 2^51231551 is an apocalyptic number.

51231551 is a deficient number, since it is larger than the sum of its proper divisors (8564929).

51231551 is a wasteful number, since it uses less digits than its factorization.

51231551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155773.

The product of its digits is 750, while the sum is 23.

The square root of 51231551 is about 7157.6218816029. The cubic root of 51231551 is about 371.4033653859.

Adding to 51231551 its reverse (15513215), we get a palindrome (66744766).

The spelling of 51231551 in words is "fifty-one million, two hundred thirty-one thousand, five hundred fifty-one".