19979040 has 96 divisors (see below), whose sum is σ = 63685440. Its totient is φ = 5264384.

The previous prime is 19979027. The next prime is 19979041. The reversal of 19979040 is 4097991.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 19979040.

It is not an unprimeable number, because it can be changed into a prime (19979041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51166 + ... + 51554.

It is an arithmetic number, because the mean of its divisors is an integer number (663390).

Almost surely, 2^19979040 is an apocalyptic number.

19979040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19979040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31842720).

19979040 is an abundant number, since it is smaller than the sum of its proper divisors (43706400).

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

19979040 is a wasteful number, since it uses less digits than its factorization.

19979040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 39.

The square root of 19979040 is about 4469.7919414666. The cubic root of 19979040 is about 271.3469048597.

The spelling of 19979040 in words is "nineteen million, nine hundred seventy-nine thousand, forty".