1981693920 has 192 divisors, whose sum is σ = 6610222080. Its totient is φ = 497645568.

The previous prime is 1981693871. The next prime is 1981693933. The reversal of 1981693920 is 293961891.

It is a super-2 number, since 2×1981693920² = 7854221585129932800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1981693920.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1796089 + ... + 1797191.

It is an arithmetic number, because the mean of its divisors is an integer number (34428240).

Almost surely, 2^1981693920 is an apocalyptic number.

1981693920 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 1981693920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3305111040).

1981693920 is an abundant number, since it is smaller than the sum of its proper divisors (4628528160).

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

1981693920 is a wasteful number, since it uses less digits than its factorization.

1981693920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337 (or 1329 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 48.

The square root of 1981693920 is about 44516.2208638604. The cubic root of 1981693920 is about 1256.0652257633.

The spelling of 1981693920 in words is "one billion, nine hundred eighty-one million, six hundred ninety-three thousand, nine hundred twenty".