20625591 has 8 divisors (see below), whose sum is σ = 31429504. Its totient is φ = 11786040.

The previous prime is 20625589. The next prime is 20625593. The reversal of 20625591 is 19552602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20625589) and next prime (20625593).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20625591 - 2¹ = 20625589 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 (20625593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 491065 + ... + 491106.

It is an arithmetic number, because the mean of its divisors is an integer number (3928688).

Almost surely, 2^20625591 is an apocalyptic number.

20625591 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20625591 is a deficient number, since it is larger than the sum of its proper divisors (10803913).

20625591 is an equidigital number, since it uses as much as digits as its factorization.

20625591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 982181.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 20625591 is about 4541.5405976386. The cubic root of 20625591 is about 274.2429470073.

The spelling of 20625591 in words is "twenty million, six hundred twenty-five thousand, five hundred ninety-one".