19720427 has 4 divisors (see below), whose sum is σ = 19744296. Its totient is φ = 19696560.

The previous prime is 19720403. The next prime is 19720447. The reversal of 19720427 is 72402791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 72402791 = 61 ⋅1186931.

It is a cyclic number.

It is not a de Polignac number, because 19720427 - 2¹² = 19716331 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19720393 and 19720402.

It is not an unprimeable number, because it can be changed into a prime (19720447) 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, 10649 + ... + 12362.

It is an arithmetic number, because the mean of its divisors is an integer number (4936074).

Almost surely, 2^19720427 is an apocalyptic number.

19720427 is a deficient number, since it is larger than the sum of its proper divisors (23869).

19720427 is an equidigital number, since it uses as much as digits as its factorization.

19720427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23868.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 19720427 is about 4440.7687397567. The cubic root of 19720427 is about 270.1710256182.

The spelling of 19720427 in words is "nineteen million, seven hundred twenty thousand, four hundred twenty-seven".