20475391 has 4 divisors (see below), whose sum is σ = 20582784. Its totient is φ = 20368000.

The previous prime is 20475383. The next prime is 20475491. The reversal of 20475391 is 19357402.

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 20475391 - 2³ = 20475383 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 (20475311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53410 + ... + 53791.

It is an arithmetic number, because the mean of its divisors is an integer number (5145696).

Almost surely, 2^20475391 is an apocalyptic number.

20475391 is a deficient number, since it is larger than the sum of its proper divisors (107393).

20475391 is a wasteful number, since it uses less digits than its factorization.

20475391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107392.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20475391 is about 4524.9741435725. The cubic root of 20475391 is about 273.5756257640.

The spelling of 20475391 in words is "twenty million, four hundred seventy-five thousand, three hundred ninety-one".