19978241 has 2 divisors, whose sum is σ = 19978242. Its totient is φ = 19978240.

The previous prime is 19978223. The next prime is 19978267. The reversal of 19978241 is 14287991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12222016 + 7756225 = 3496^2 + 2785^2 .

It is a cyclic number.

It is not a de Polignac number, because 19978241 - 2¹⁴ = 19961857 is a prime.

It is a super-2 number, since 2×19978241² = 798260226908162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19978271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989120 + 9989121.

It is an arithmetic number, because the mean of its divisors is an integer number (9989121).

Almost surely, 2^19978241 is an apocalyptic number.

It is an amenable number.

19978241 is a deficient number, since it is larger than the sum of its proper divisors (1).

19978241 is an equidigital number, since it uses as much as digits as its factorization.

19978241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 41.

The square root of 19978241 is about 4469.7025628111. The cubic root of 19978241 is about 271.3432875844.

The spelling of 19978241 in words is "nineteen million, nine hundred seventy-eight thousand, two hundred forty-one".