19878981 has 8 divisors (see below), whose sum is σ = 26573664. Its totient is φ = 13218480.

The previous prime is 19878941. The next prime is 19878983. The reversal of 19878981 is 18987891.

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

It is not a de Polignac number, because 19878981 - 2⁶ = 19878917 is a prime.

It is a super-2 number, since 2×19878981² = 790347771196722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19878983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7155 + ... + 9536.

It is an arithmetic number, because the mean of its divisors is an integer number (3321708).

Almost surely, 2^19878981 is an apocalyptic number.

It is an amenable number.

19878981 is a deficient number, since it is larger than the sum of its proper divisors (6694683).

19878981 is a wasteful number, since it uses less digits than its factorization.

19878981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17091.

The product of its digits is 290304, while the sum is 51.

The square root of 19878981 is about 4458.5850894650. The cubic root of 19878981 is about 270.8931601377.

The spelling of 19878981 in words is "nineteen million, eight hundred seventy-eight thousand, nine hundred eighty-one".