20256491 has 8 divisors (see below), whose sum is σ = 21337344. Its totient is φ = 19192360.

The previous prime is 20256479. The next prime is 20256497. The reversal of 20256491 is 19465202.

It is a happy number.

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 20256491 - 2¹⁴ = 20240107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20256497) 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, 1655 + ... + 6576.

It is an arithmetic number, because the mean of its divisors is an integer number (2667168).

Almost surely, 2^20256491 is an apocalyptic number.

20256491 is a deficient number, since it is larger than the sum of its proper divisors (1080853).

20256491 is a wasteful number, since it uses less digits than its factorization.

20256491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8361.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 20256491 is about 4500.7211644358. The cubic root of 20256491 is about 272.5972090970.

The spelling of 20256491 in words is "twenty million, two hundred fifty-six thousand, four hundred ninety-one".