19109840 has 40 divisors (see below), whose sum is σ = 45968040. Its totient is φ = 7379456.

The previous prime is 19109809. The next prime is 19109851. The reversal of 19109840 is 4890191.

19109840 = T₂₇₃ + T₂₇₄ + ... + T₅₁₂.

It can be written as a sum of positive squares in 4 ways, for example, as 2917264 + 16192576 = 1708^2 + 4024^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 19109797 and 19109806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1799 + ... + 6438.

It is an arithmetic number, because the mean of its divisors is an integer number (1149201).

Almost surely, 2^19109840 is an apocalyptic number.

19109840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19109840 is an abundant number, since it is smaller than the sum of its proper divisors (26858200).

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

19109840 is a wasteful number, since it uses less digits than its factorization.

19109840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8279 (or 8273 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 19109840 is about 4371.4802984801. The cubic root of 19109840 is about 267.3533828381.

The spelling of 19109840 in words is "nineteen million, one hundred nine thousand, eight hundred forty".