19779990 has 16 divisors (see below), whose sum is σ = 47472048. Its totient is φ = 5274656.

The previous prime is 19779973. The next prime is 19780009. The reversal of 19779990 is 9997791.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 329637 + ... + 329696.

It is an arithmetic number, because the mean of its divisors is an integer number (2967003).

Almost surely, 2^19779990 is an apocalyptic number.

19779990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19779990 is an abundant number, since it is smaller than the sum of its proper divisors (27692058).

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

19779990 is a wasteful number, since it uses less digits than its factorization.

19779990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659343.

The product of its (nonzero) digits is 321489, while the sum is 51.

The square root of 19779990 is about 4447.4700673529. The cubic root of 19779990 is about 270.4427577746.

The spelling of 19779990 in words is "nineteen million, seven hundred seventy-nine thousand, nine hundred ninety".