20452391 has 4 divisors (see below), whose sum is σ = 20928072. Its totient is φ = 19976712.

The previous prime is 20452363. The next prime is 20452427. The reversal of 20452391 is 19325402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19325402 = 2 ⋅9662701.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20452391 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20452391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20457391) 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, 237776 + ... + 237861.

It is an arithmetic number, because the mean of its divisors is an integer number (5232018).

Almost surely, 2^20452391 is an apocalyptic number.

20452391 is a deficient number, since it is larger than the sum of its proper divisors (475681).

20452391 is an equidigital number, since it uses as much as digits as its factorization.

20452391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475680.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20452391 is about 4522.4319784824. The cubic root of 20452391 is about 273.4731515811.

Adding to 20452391 its reverse (19325402), we get a palindrome (39777793).

The spelling of 20452391 in words is "twenty million, four hundred fifty-two thousand, three hundred ninety-one".