19990440 has 48 divisors (see below), whose sum is σ = 64970100. Its totient is φ = 5330688.

The previous prime is 19990433. The next prime is 19990447. The reversal of 19990440 is 4409991.

It is an interprime number because it is at equal distance from previous prime (19990433) and next prime (19990447).

It can be written as a sum of positive squares in 2 ways, for example, as 16597476 + 3392964 = 4074^2 + 1842^2 .

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 19990395 and 19990404.

It is not an unprimeable number, because it can be changed into a prime (19990447) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27405 + ... + 28124.

Almost surely, 2^19990440 is an apocalyptic number.

19990440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19990440 is an abundant number, since it is smaller than the sum of its proper divisors (44979660).

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

19990440 is a wasteful number, since it uses less digits than its factorization.

19990440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55546 (or 55539 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 19990440 is about 4471.0669867494. The cubic root of 19990440 is about 271.3985050458.

The spelling of 19990440 in words is "nineteen million, nine hundred ninety thousand, four hundred forty".