18971916 has 24 divisors (see below), whose sum is σ = 45795120. Its totient is φ = 6105792.

The previous prime is 18971903. The next prime is 18971917. The reversal of 18971916 is 61917981.

It is a super-2 number, since 2×18971916² = 719867193422112, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18971917) 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 7 ways as a sum of consecutive naturals, for example, 26911 + ... + 27606.

It is an arithmetic number, because the mean of its divisors is an integer number (1908130).

Almost surely, 2^18971916 is an apocalyptic number.

It is an amenable number.

18971916 is an abundant number, since it is smaller than the sum of its proper divisors (26823204).

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

18971916 is a wasteful number, since it uses less digits than its factorization.

18971916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54553 (or 54551 counting only the distinct ones).

The product of its digits is 27216, while the sum is 42.

The square root of 18971916 is about 4355.6762965124. The cubic root of 18971916 is about 266.7086274248.

The spelling of 18971916 in words is "eighteen million, nine hundred seventy-one thousand, nine hundred sixteen".