19899640 has 16 divisors (see below), whose sum is σ = 44774280. Its totient is φ = 7959840.

The previous prime is 19899629. The next prime is 19899641. The reversal of 19899640 is 4699891.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19899641) 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, 248706 + ... + 248785.

Almost surely, 2^19899640 is an apocalyptic number.

19899640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19899640 is an abundant number, since it is smaller than the sum of its proper divisors (24874640).

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

19899640 is a wasteful number, since it uses less digits than its factorization.

19899640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497502 (or 497498 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 46.

The square root of 19899640 is about 4460.9012542310. The cubic root of 19899640 is about 270.9869685051.

The spelling of 19899640 in words is "nineteen million, eight hundred ninety-nine thousand, six hundred forty".