61646991 has 8 divisors (see below), whose sum is σ = 93938304. Its totient is φ = 35226840.

The previous prime is 61646989. The next prime is 61647017. The reversal of 61646991 is 19964616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61646991 - 2¹ = 61646989 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61646911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1467765 + ... + 1467806.

It is an arithmetic number, because the mean of its divisors is an integer number (11742288).

Almost surely, 2^61646991 is an apocalyptic number.

61646991 is a deficient number, since it is larger than the sum of its proper divisors (32291313).

61646991 is a wasteful number, since it uses less digits than its factorization.

61646991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2935581.

The product of its digits is 69984, while the sum is 42.

The square root of 61646991 is about 7851.5597813428. The cubic root of 61646991 is about 395.0365634049.

The spelling of 61646991 in words is "sixty-one million, six hundred forty-six thousand, nine hundred ninety-one".