61668491 has 4 divisors (see below), whose sum is σ = 61733232. Its totient is φ = 61603752.

The previous prime is 61668473. The next prime is 61668527. The reversal of 61668491 is 19486616.

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 61668491 - 2¹⁰ = 61667467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61668421) 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, 30920 + ... + 32853.

It is an arithmetic number, because the mean of its divisors is an integer number (15433308).

Almost surely, 2^61668491 is an apocalyptic number.

61668491 is a deficient number, since it is larger than the sum of its proper divisors (64741).

61668491 is an equidigital number, since it uses as much as digits as its factorization.

61668491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64740.

The product of its digits is 62208, while the sum is 41.

The square root of 61668491 is about 7852.9288166900. The cubic root of 61668491 is about 395.0824823746.

The spelling of 61668491 in words is "sixty-one million, six hundred sixty-eight thousand, four hundred ninety-one".