99991540 has 24 divisors (see below), whose sum is σ = 229072032. Its totient is φ = 36360480.

The previous prime is 99991519. The next prime is 99991559. The reversal of 99991540 is 4519999.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 227034 + ... + 227473.

It is an arithmetic number, because the mean of its divisors is an integer number (9544668).

Almost surely, 2^99991540 is an apocalyptic number.

It is an amenable number.

99991540 is an abundant number, since it is smaller than the sum of its proper divisors (129080492).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99991540 is a wasteful number, since it uses less digits than its factorization.

99991540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454527 (or 454525 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 46.

The square root of 99991540 is about 9999.5769910532. The cubic root of 99991540 is about 464.1457937116.

The spelling of 99991540 in words is "ninety-nine million, nine hundred ninety-one thousand, five hundred forty".