19971020 has 12 divisors (see below), whose sum is σ = 41939184. Its totient is φ = 7988400.

The previous prime is 19971019. The next prime is 19971023. The reversal of 19971020 is 2017991.

19971020 = 687² + 688² + ... + 726².

It is not an unprimeable number, because it can be changed into a prime (19971023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 499256 + ... + 499295.

It is an arithmetic number, because the mean of its divisors is an integer number (3494932).

Almost surely, 2^19971020 is an apocalyptic number.

19971020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19971020 is an abundant number, since it is smaller than the sum of its proper divisors (21968164).

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

19971020 is a wasteful number, since it uses less digits than its factorization.

19971020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998560 (or 998558 counting only the distinct ones).

The product of its (nonzero) digits is 1134, while the sum is 29.

The square root of 19971020 is about 4468.8947179364. The cubic root of 19971020 is about 271.3105919132.

The spelling of 19971020 in words is "nineteen million, nine hundred seventy-one thousand, twenty".