20019523 has 4 divisors (see below), whose sum is σ = 21197160. Its totient is φ = 18841888.

The previous prime is 20019511. The next prime is 20019547. The reversal of 20019523 is 32591002.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20019523 is a prime.

It is a super-2 number, since 2×20019523² = 801562602295058, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20019494 and 20019503.

It is not an unprimeable number, because it can be changed into a prime (20019023) 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, 588793 + ... + 588826.

It is an arithmetic number, because the mean of its divisors is an integer number (5299290).

Almost surely, 2^20019523 is an apocalyptic number.

20019523 is a deficient number, since it is larger than the sum of its proper divisors (1177637).

20019523 is a wasteful number, since it uses less digits than its factorization.

20019523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1177636.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 20019523 is about 4474.3181603458. The cubic root of 20019523 is about 271.5300555616.

The spelling of 20019523 in words is "twenty million, nineteen thousand, five hundred twenty-three".