20257391 has 8 divisors (see below), whose sum is σ = 25256064. Its totient is φ = 15784920.

The previous prime is 20257373. The next prime is 20257451. The reversal of 20257391 is 19375202.

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

It is a cyclic number.

It is not a de Polignac number, because 20257391 - 2⁶ = 20257327 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 (20257301) 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, 131465 + ... + 131618.

It is an arithmetic number, because the mean of its divisors is an integer number (3157008).

Almost surely, 2^20257391 is an apocalyptic number.

20257391 is a deficient number, since it is larger than the sum of its proper divisors (4998673).

20257391 is a wasteful number, since it uses less digits than its factorization.

20257391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263101.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 20257391 is about 4500.8211473019. The cubic root of 20257391 is about 272.6012462203.

The spelling of 20257391 in words is "twenty million, two hundred fifty-seven thousand, three hundred ninety-one".