71491987 has 16 divisors (see below), whose sum is σ = 88627392. Its totient is φ = 56263680.

The previous prime is 71491961. The next prime is 71491997. The reversal of 71491987 is 78919417.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71491987 is a prime.

It is a super-2 number, since 2×71491987² = 10222208410416338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (71491997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2448 + ... + 12205.

It is an arithmetic number, because the mean of its divisors is an integer number (5539212).

Almost surely, 2^71491987 is an apocalyptic number.

71491987 is a deficient number, since it is larger than the sum of its proper divisors (17135405).

71491987 is a wasteful number, since it uses less digits than its factorization.

71491987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14718.

The product of its digits is 127008, while the sum is 46.

The square root of 71491987 is about 8455.2934307450. The cubic root of 71491987 is about 415.0360195184.

The spelling of 71491987 in words is "seventy-one million, four hundred ninety-one thousand, nine hundred eighty-seven".