71978111 has 4 divisors (see below), whose sum is σ = 72009000. Its totient is φ = 71947224.

The previous prime is 71978107. The next prime is 71978117. The reversal of 71978111 is 11187917.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11187917 = 13 ⋅860609.

It is a cyclic number.

It is not a de Polignac number, because 71978111 - 2² = 71978107 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 (71978117) 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, 11636 + ... + 16713.

It is an arithmetic number, because the mean of its divisors is an integer number (18002250).

Almost surely, 2^71978111 is an apocalyptic number.

71978111 is a deficient number, since it is larger than the sum of its proper divisors (30889).

71978111 is a wasteful number, since it uses less digits than its factorization.

71978111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30888.

The product of its digits is 3528, while the sum is 35.

The square root of 71978111 is about 8483.9914544983. The cubic root of 71978111 is about 415.9746020459.

The spelling of 71978111 in words is "seventy-one million, nine hundred seventy-eight thousand, one hundred eleven".