20154391 has 4 divisors (see below), whose sum is σ = 20849400. Its totient is φ = 19459384.

The previous prime is 20154389. The next prime is 20154403. The reversal of 20154391 is 19345102.

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 20154391 - 2¹ = 20154389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20154311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347461 + ... + 347518.

It is an arithmetic number, because the mean of its divisors is an integer number (5212350).

Almost surely, 2^20154391 is an apocalyptic number.

20154391 is a deficient number, since it is larger than the sum of its proper divisors (695009).

20154391 is an equidigital number, since it uses as much as digits as its factorization.

20154391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695008.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 20154391 is about 4489.3642088830. The cubic root of 20154391 is about 272.1384414552.

Adding to 20154391 its reverse (19345102), we get a palindrome (39499493).

The spelling of 20154391 in words is "twenty million, one hundred fifty-four thousand, three hundred ninety-one".