19701681 has 4 divisors (see below), whose sum is σ = 26268912. Its totient is φ = 13134452.

The previous prime is 19701679. The next prime is 19701707. The reversal of 19701681 is 18610791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19701681 - 2¹ = 19701679 is a prime.

It is a super-2 number, since 2×19701681² = 776312468451522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19701631) 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, 3283611 + ... + 3283616.

It is an arithmetic number, because the mean of its divisors is an integer number (6567228).

Almost surely, 2^19701681 is an apocalyptic number.

It is an amenable number.

19701681 is a deficient number, since it is larger than the sum of its proper divisors (6567231).

19701681 is an equidigital number, since it uses as much as digits as its factorization.

19701681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6567230.

The product of its (nonzero) digits is 3024, while the sum is 33.

The square root of 19701681 is about 4438.6575673282. The cubic root of 19701681 is about 270.0853913723.

The spelling of 19701681 in words is "nineteen million, seven hundred one thousand, six hundred eighty-one".