19699981 has 8 divisors (see below), whose sum is σ = 22555904. Its totient is φ = 16854480.

The previous prime is 19699969. The next prime is 19699987. The reversal of 19699981 is 18999691.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19699981 is a prime.

It is a super-2 number, since 2×19699981² = 776178502800722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19699987) 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 7 ways as a sum of consecutive naturals, for example, 1996 + ... + 6586.

It is an arithmetic number, because the mean of its divisors is an integer number (2819488).

Almost surely, 2^19699981 is an apocalyptic number.

It is an amenable number.

19699981 is a deficient number, since it is larger than the sum of its proper divisors (2855923).

19699981 is an equidigital number, since it uses as much as digits as its factorization.

19699981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5211.

The product of its digits is 314928, while the sum is 52.

The square root of 19699981 is about 4438.4660638558. The cubic root of 19699981 is about 270.0776228579.

The spelling of 19699981 in words is "nineteen million, six hundred ninety-nine thousand, nine hundred eighty-one".