20190581 has 4 divisors (see below), whose sum is σ = 20202432. Its totient is φ = 20178732.

The previous prime is 20190563. The next prime is 20190593. The reversal of 20190581 is 18509102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20190581 is a prime.

It is a super-2 number, since 2×20190581² = 815319122235122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20190581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20190551) 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, 2831 + ... + 6956.

It is an arithmetic number, because the mean of its divisors is an integer number (5050608).

Almost surely, 2^20190581 is an apocalyptic number.

It is an amenable number.

20190581 is a deficient number, since it is larger than the sum of its proper divisors (11851).

20190581 is an equidigital number, since it uses as much as digits as its factorization.

20190581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11850.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 20190581 is about 4493.3930386736. The cubic root of 20190581 is about 272.3012314757.

Adding to 20190581 its reverse (18509102), we get a palindrome (38699683).

The spelling of 20190581 in words is "twenty million, one hundred ninety thousand, five hundred eighty-one".