19421990 has 64 divisors (see below), whose sum is σ = 44582400. Its totient is φ = 5930496.

The previous prime is 19421981. The next prime is 19422017. The reversal of 19421990 is 9912491.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 19421990.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22181 + ... + 23039.

It is an arithmetic number, because the mean of its divisors is an integer number (696600).

Almost surely, 2^19421990 is an apocalyptic number.

19421990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19421990 is an abundant number, since it is smaller than the sum of its proper divisors (25160410).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19421990 is a wasteful number, since it uses less digits than its factorization.

19421990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909.

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 19421990 is about 4407.0386882804. The cubic root of 19421990 is about 268.8012240561.

The spelling of 19421990 in words is "nineteen million, four hundred twenty-one thousand, nine hundred ninety".