70491991 has 4 divisors (see below), whose sum is σ = 70732872. Its totient is φ = 70251112.

The previous prime is 70491977. The next prime is 70492001. The reversal of 70491991 is 19919407.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19919407 = 769 ⋅25903.

It is a cyclic number.

It is not a de Polignac number, because 70491991 - 2⁵ = 70491959 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (70491931) 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, 120001 + ... + 120586.

It is an arithmetic number, because the mean of its divisors is an integer number (17683218).

Almost surely, 2^70491991 is an apocalyptic number.

70491991 is a deficient number, since it is larger than the sum of its proper divisors (240881).

70491991 is a wasteful number, since it uses less digits than its factorization.

70491991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240880.

The product of its (nonzero) digits is 20412, while the sum is 40.

The square root of 70491991 is about 8395.9508693179. The cubic root of 70491991 is about 413.0918172977.

The spelling of 70491991 in words is "seventy million, four hundred ninety-one thousand, nine hundred ninety-one".