66312551 has 4 divisors (see below), whose sum is σ = 67399704. Its totient is φ = 65225400.

The previous prime is 66312517. The next prime is 66312577. The reversal of 66312551 is 15521366.

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 66312551 - 2¹⁰ = 66311527 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 (66312511) 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, 543485 + ... + 543606.

It is an arithmetic number, because the mean of its divisors is an integer number (16849926).

Almost surely, 2^66312551 is an apocalyptic number.

66312551 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66312551 is a deficient number, since it is larger than the sum of its proper divisors (1087153).

66312551 is a wasteful number, since it uses less digits than its factorization.

66312551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1087152.

The product of its digits is 5400, while the sum is 29.

The square root of 66312551 is about 8143.2518688789. The cubic root of 66312551 is about 404.7609237766.

The spelling of 66312551 in words is "sixty-six million, three hundred twelve thousand, five hundred fifty-one".