19956981 has 16 divisors (see below), whose sum is σ = 29122560. Its totient is φ = 12055920.

The previous prime is 19956961. The next prime is 19957009. The reversal of 19956981 is 18965991.

It is not a de Polignac number, because 19956981 - 2⁶ = 19956917 is a prime.

It is a super-2 number, since 2×19956981² = 796562181268722, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19956981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19956941) 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 15 ways as a sum of consecutive naturals, for example, 11850 + ... + 13428.

It is an arithmetic number, because the mean of its divisors is an integer number (1820160).

Almost surely, 2^19956981 is an apocalyptic number.

19956981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19956981 is a deficient number, since it is larger than the sum of its proper divisors (9165579).

19956981 is a wasteful number, since it uses less digits than its factorization.

19956981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1976.

The product of its digits is 174960, while the sum is 48.

The square root of 19956981 is about 4467.3236954579. The cubic root of 19956981 is about 271.2470027347.

The spelling of 19956981 in words is "nineteen million, nine hundred fifty-six thousand, nine hundred eighty-one".