19428987 has 4 divisors (see below), whose sum is σ = 25905320. Its totient is φ = 12952656.

The previous prime is 19428979. The next prime is 19428989. The reversal of 19428987 is 78982491.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 19428987 - 2³ = 19428979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19428989) 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, 3238162 + ... + 3238167.

It is an arithmetic number, because the mean of its divisors is an integer number (6476330).

Almost surely, 2^19428987 is an apocalyptic number.

19428987 is a deficient number, since it is larger than the sum of its proper divisors (6476333).

19428987 is an equidigital number, since it uses as much as digits as its factorization.

19428987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6476332.

The product of its digits is 290304, while the sum is 48.

The square root of 19428987 is about 4407.8324605184. The cubic root of 19428987 is about 268.8334997798.

It can be divided in two parts, 194289 and 87, that added together give a triangular number (194376 = T₆₂₃).

The spelling of 19428987 in words is "nineteen million, four hundred twenty-eight thousand, nine hundred eighty-seven".