70999991 has 4 divisors (see below), whose sum is σ = 71027472. Its totient is φ = 70972512.

The previous prime is 70999961. The next prime is 70999997. The reversal of 70999991 is 19999907.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19999907 = 3067 ⋅6521.

It is a cyclic number.

It is not a de Polignac number, because 70999991 - 2⁶ = 70999927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (70999997) 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, 9410 + ... + 15183.

It is an arithmetic number, because the mean of its divisors is an integer number (17756868).

Almost surely, 2^70999991 is an apocalyptic number.

70999991 is a deficient number, since it is larger than the sum of its proper divisors (27481).

70999991 is a wasteful number, since it uses less digits than its factorization.

70999991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27480.

The product of its (nonzero) digits is 413343, while the sum is 53.

The square root of 70999991 is about 8426.1492391246. The cubic root of 70999991 is about 414.0817574459.

The spelling of 70999991 in words is "seventy million, nine hundred ninety-nine thousand, nine hundred ninety-one".