66491641398 has 64 divisors (see below), whose sum is σ = 168951508992. Its totient is φ = 16970567040.

The previous prime is 66491641397. The next prime is 66491641399. The reversal of 66491641398 is 89314619466.

It is an interprime number because it is at equal distance from previous prime (66491641397) and next prime (66491641399).

It is a super-2 number, since 2×66491641398² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66491641397) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1947261 + ... + 1981112.

It is an arithmetic number, because the mean of its divisors is an integer number (2639867328).

Almost surely, 2^66491641398 is an apocalyptic number.

66491641398 is an abundant number, since it is smaller than the sum of its proper divisors (102459867594).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66491641398 is a wasteful number, since it uses less digits than its factorization.

66491641398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3928429.

The product of its digits is 6718464, while the sum is 57.

The spelling of 66491641398 in words is "sixty-six billion, four hundred ninety-one million, six hundred forty-one thousand, three hundred ninety-eight".