20019990 has 16 divisors (see below), whose sum is σ = 48048048. Its totient is φ = 5338656.

The previous prime is 20019973. The next prime is 20020001. The reversal of 20019990 is 9991002.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 667333 = 20019990 / (2 + 0 + 0 + 1 + 9 + 9 + 9 + 0).

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, 333637 + ... + 333696.

It is an arithmetic number, because the mean of its divisors is an integer number (3003003).

Almost surely, 2^20019990 is an apocalyptic number.

20019990 is an abundant number, since it is smaller than the sum of its proper divisors (28028058).

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

20019990 is a wasteful number, since it uses less digits than its factorization.

20019990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667343.

The product of its (nonzero) digits is 1458, while the sum is 30.

The square root of 20019990 is about 4474.3703467639. The cubic root of 20019990 is about 271.5321668931.

The spelling of 20019990 in words is "twenty million, nineteen thousand, nine hundred ninety".