20381623 has 16 divisors (see below), whose sum is σ = 23004000. Its totient is φ = 17943552.

The previous prime is 20381593. The next prime is 20381651. The reversal of 20381623 is 32618302.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20381623 is a prime.

It is a super-2 number, since 2×20381623² = 830821112228258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20381653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28393 + ... + 29101.

It is an arithmetic number, because the mean of its divisors is an integer number (1437750).

Almost surely, 2^20381623 is an apocalyptic number.

20381623 is a deficient number, since it is larger than the sum of its proper divisors (2622377).

20381623 is a wasteful number, since it uses less digits than its factorization.

20381623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 834.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 20381623 is about 4514.6010897974. The cubic root of 20381623 is about 273.1573692277.

Adding to 20381623 its reverse (32618302), we get a palindrome (52999925).

The spelling of 20381623 in words is "twenty million, three hundred eighty-one thousand, six hundred twenty-three".