20925391 has 4 divisors (see below), whose sum is σ = 21412072. Its totient is φ = 20438712.

The previous prime is 20925389. The next prime is 20925433. The reversal of 20925391 is 19352902.

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 20925391 - 2¹ = 20925389 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 (20925361) 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, 243276 + ... + 243361.

It is an arithmetic number, because the mean of its divisors is an integer number (5353018).

Almost surely, 2^20925391 is an apocalyptic number.

20925391 is a deficient number, since it is larger than the sum of its proper divisors (486681).

20925391 is an equidigital number, since it uses as much as digits as its factorization.

20925391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486680.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 20925391 is about 4574.4279423771. The cubic root of 20925391 is about 275.5652988652.

It can be divided in two parts, 20925 and 391, that added together give a square (21316 = 146²).

The spelling of 20925391 in words is "twenty million, nine hundred twenty-five thousand, three hundred ninety-one".