19916091 has 32 divisors (see below), whose sum is σ = 33169920. Its totient is φ = 11718432.

The previous prime is 19916087. The next prime is 19916173. The reversal of 19916091 is 19061991.

It is not a de Polignac number, because 19916091 - 2² = 19916087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19916021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6840 + ... + 9306.

It is an arithmetic number, because the mean of its divisors is an integer number (1036560).

Almost surely, 2^19916091 is an apocalyptic number.

19916091 is a deficient number, since it is larger than the sum of its proper divisors (13253829).

19916091 is a wasteful number, since it uses less digits than its factorization.

19916091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2512 (or 2506 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 36.

The square root of 19916091 is about 4462.7447832024. The cubic root of 19916091 is about 271.0616227652.

It can be divided in two parts, 199 and 16091, that added together give a triangular number (16290 = T₁₈₀).

The spelling of 19916091 in words is "nineteen million, nine hundred sixteen thousand, ninety-one".