70991891 has 8 divisors (see below), whose sum is σ = 73497600. Its totient is φ = 68499720.

The previous prime is 70991873. The next prime is 70991909. The reversal of 70991891 is 19819907.

It is an interprime number because it is at equal distance from previous prime (70991873) and next prime (70991909).

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

It is a cyclic number.

It is not a de Polignac number, because 70991891 - 2²² = 66797587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70991801) 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, 7940 + ... + 14318.

It is an arithmetic number, because the mean of its divisors is an integer number (9187200).

Almost surely, 2^70991891 is an apocalyptic number.

70991891 is a deficient number, since it is larger than the sum of its proper divisors (2505709).

70991891 is a wasteful number, since it uses less digits than its factorization.

70991891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6769.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 70991891 is about 8425.6685788132. The cubic root of 70991891 is about 414.0660100740.

The spelling of 70991891 in words is "seventy million, nine hundred ninety-one thousand, eight hundred ninety-one".