20445431 has 4 divisors (see below), whose sum is σ = 20780664. Its totient is φ = 20110200.

The previous prime is 20445427. The next prime is 20445443. The reversal of 20445431 is 13454402.

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

It is a cyclic number.

It is not a de Polignac number, because 20445431 - 2² = 20445427 is a prime.

It is a super-2 number, since 2×20445431² = 836031297551522, 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 = 20445397 and 20445406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20415431) 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, 167525 + ... + 167646.

It is an arithmetic number, because the mean of its divisors is an integer number (5195166).

Almost surely, 2^20445431 is an apocalyptic number.

20445431 is a deficient number, since it is larger than the sum of its proper divisors (335233).

20445431 is an equidigital number, since it uses as much as digits as its factorization.

20445431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335232.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20445431 is about 4521.6624155282. The cubic root of 20445431 is about 273.4421268616.

Adding to 20445431 its reverse (13454402), we get a palindrome (33899833).

The spelling of 20445431 in words is "twenty million, four hundred forty-five thousand, four hundred thirty-one".