991896487 has 4 divisors (see below), whose sum is σ = 995025816. Its totient is φ = 988767160.

The previous prime is 991896461. The next prime is 991896497. The reversal of 991896487 is 784698199.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 991896487 - 2²³ = 983507879 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 (991896497) 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, 1564189 + ... + 1564822.

It is an arithmetic number, because the mean of its divisors is an integer number (248756454).

Almost surely, 2^991896487 is an apocalyptic number.

991896487 is a deficient number, since it is larger than the sum of its proper divisors (3129329).

991896487 is a wasteful number, since it uses less digits than its factorization.

991896487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3129328.

The product of its digits is 7838208, while the sum is 61.

The square root of 991896487 is about 31494.3881826588. The cubic root of 991896487 is about 997.2914996490.

The spelling of 991896487 in words is "nine hundred ninety-one million, eight hundred ninety-six thousand, four hundred eighty-seven".