19642981 has 4 divisors (see below), whose sum is σ = 19651852. Its totient is φ = 19634112.

The previous prime is 19642969. The next prime is 19643003. The reversal of 19642981 is 18924691.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3118756 + 16524225 = 1766^2 + 4065^2 .

It is a cyclic number.

It is not a de Polignac number, because 19642981 - 2⁵ = 19642949 is a prime.

It is a super-2 number, since 2×19642981² = 771693405132722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19642081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1975 + ... + 6571.

It is an arithmetic number, because the mean of its divisors is an integer number (4912963).

Almost surely, 2^19642981 is an apocalyptic number.

It is an amenable number.

19642981 is a deficient number, since it is larger than the sum of its proper divisors (8871).

19642981 is an equidigital number, since it uses as much as digits as its factorization.

19642981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8870.

The product of its digits is 31104, while the sum is 40.

The square root of 19642981 is about 4432.0402750878. The cubic root of 19642981 is about 269.8168900203.

The spelling of 19642981 in words is "nineteen million, six hundred forty-two thousand, nine hundred eighty-one".