19997020 has 48 divisors (see below), whose sum is σ = 43934688. Its totient is φ = 7637760.

The previous prime is 19997017. The next prime is 19997023. The reversal of 19997020 is 2079991.

It is an interprime number because it is at equal distance from previous prime (19997017) and next prime (19997023).

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997023) 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, 44919 + ... + 45361.

It is an arithmetic number, because the mean of its divisors is an integer number (915306).

Almost surely, 2^19997020 is an apocalyptic number.

19997020 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 19997020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21967344).

19997020 is an abundant number, since it is smaller than the sum of its proper divisors (23937668).

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

19997020 is a wasteful number, since it uses less digits than its factorization.

19997020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550 (or 548 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 37.

The square root of 19997020 is about 4471.8027684593. The cubic root of 19997020 is about 271.4282793824.

The spelling of 19997020 in words is "nineteen million, nine hundred ninety-seven thousand, twenty".