19427991 has 16 divisors (see below), whose sum is σ = 29922048. Its totient is φ = 11081600.

The previous prime is 19427953. The next prime is 19428011. The reversal of 19427991 is 19972491.

It is a cyclic number.

It is not a de Polignac number, because 19427991 - 2¹⁴ = 19411607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19427911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16755 + ... + 17876.

It is an arithmetic number, because the mean of its divisors is an integer number (1870128).

Almost surely, 2^19427991 is an apocalyptic number.

19427991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19427991 is a deficient number, since it is larger than the sum of its proper divisors (10494057).

19427991 is a wasteful number, since it uses less digits than its factorization.

19427991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34662.

The product of its digits is 40824, while the sum is 42.

The square root of 19427991 is about 4407.7194783697. The cubic root of 19427991 is about 268.8289059095.

The spelling of 19427991 in words is "nineteen million, four hundred twenty-seven thousand, nine hundred ninety-one".