1989720 has 48 divisors (see below), whose sum is σ = 6467760. Its totient is φ = 530496.

The previous prime is 1989683. The next prime is 1989721. The reversal of 1989720 is 279891.

It is a happy number.

It is a Smith number, since the sum of its digits (36) 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 (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2404 + ... + 3123.

It is an arithmetic number, because the mean of its divisors is an integer number (134745).

2^1989720 is an apocalyptic number.

1989720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1989720 is an abundant number, since it is smaller than the sum of its proper divisors (4478040).

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

1989720 is a wasteful number, since it uses less digits than its factorization.

1989720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5544 (or 5537 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 1989720 is about 1410.5743511067. The cubic root of 1989720 is about 125.7758676053.

The spelling of 1989720 in words is "one million, nine hundred eighty-nine thousand, seven hundred twenty".