19687641 has 4 divisors (see below), whose sum is σ = 26250192. Its totient is φ = 13125092.

The previous prime is 19687639. The next prime is 19687693. The reversal of 19687641 is 14678691.

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, and also an emirpimes, since its reverse is a distinct semiprime: 14678691 = 3 ⋅4892897.

It is a cyclic number.

It is not a de Polignac number, because 19687641 - 2¹ = 19687639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19687593 and 19687602.

It is not an unprimeable number, because it can be changed into a prime (19687631) 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, 3281271 + ... + 3281276.

It is an arithmetic number, because the mean of its divisors is an integer number (6562548).

Almost surely, 2^19687641 is an apocalyptic number.

It is an amenable number.

19687641 is a deficient number, since it is larger than the sum of its proper divisors (6562551).

19687641 is an equidigital number, since it uses as much as digits as its factorization.

19687641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6562550.

The product of its digits is 72576, while the sum is 42.

The square root of 19687641 is about 4437.0757261963. The cubic root of 19687641 is about 270.0212191828.

The spelling of 19687641 in words is "nineteen million, six hundred eighty-seven thousand, six hundred forty-one".