66992491 has 4 divisors (see below), whose sum is σ = 69905232. Its totient is φ = 64079752.

The previous prime is 66992489. The next prime is 66992501. The reversal of 66992491 is 19429966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19429966 = 2 ⋅9714983.

It is a cyclic number.

It is not a de Polignac number, because 66992491 - 2¹ = 66992489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66992441) 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, 1456336 + ... + 1456381.

It is an arithmetic number, because the mean of its divisors is an integer number (17476308).

Almost surely, 2^66992491 is an apocalyptic number.

66992491 is a deficient number, since it is larger than the sum of its proper divisors (2912741).

66992491 is a wasteful number, since it uses less digits than its factorization.

66992491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2912740.

The product of its digits is 209952, while the sum is 46.

The square root of 66992491 is about 8184.8940738412. The cubic root of 66992491 is about 406.1396362614.

The spelling of 66992491 in words is "sixty-six million, nine hundred ninety-two thousand, four hundred ninety-one".