19890440 has 16 divisors (see below), whose sum is σ = 44753580. Its totient is φ = 7956160.

The previous prime is 19890439. The next prime is 19890443. The reversal of 19890440 is 4409891.

It can be written as a sum of positive squares in 2 ways, for example, as 19483396 + 407044 = 4414^2 + 638^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 19890440.

It is not an unprimeable number, because it can be changed into a prime (19890443) 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, 248591 + ... + 248670.

Almost surely, 2^19890440 is an apocalyptic number.

19890440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19890440 is an abundant number, since it is smaller than the sum of its proper divisors (24863140).

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

19890440 is a wasteful number, since it uses less digits than its factorization.

19890440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497272 (or 497268 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 19890440 is about 4459.8699532610. The cubic root of 19890440 is about 270.9452011764.

It can be divided in two parts, 198 and 90440, that multiplied together give a triangular number (17907120 = T₅₉₈₄).

The spelling of 19890440 in words is "nineteen million, eight hundred ninety thousand, four hundred forty".