66549951 has 64 divisors (see below), whose sum is σ = 118540800. Its totient is φ = 36453888.

The previous prime is 66549947. The next prime is 66549991. The reversal of 66549951 is 15994566.

It is a happy number.

It is not a de Polignac number, because 66549951 - 2² = 66549947 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 66549897 and 66549906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66549911) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 113080 + ... + 113666.

It is an arithmetic number, because the mean of its divisors is an integer number (1852200).

Almost surely, 2^66549951 is an apocalyptic number.

66549951 is a deficient number, since it is larger than the sum of its proper divisors (51990849).

66549951 is a wasteful number, since it uses less digits than its factorization.

66549951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645 (or 639 counting only the distinct ones).

The product of its digits is 291600, while the sum is 45.

The square root of 66549951 is about 8157.8153325507. The cubic root of 66549951 is about 405.2433653917.

The spelling of 66549951 in words is "sixty-six million, five hundred forty-nine thousand, nine hundred fifty-one".