20581247 has 8 divisors (see below), whose sum is σ = 20829312. Its totient is φ = 20335000.

The previous prime is 20581243. The next prime is 20581259. The reversal of 20581247 is 74218502.

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 20581247 - 2² = 20581243 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 (20581243) 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, 41672 + ... + 42162.

It is an arithmetic number, because the mean of its divisors is an integer number (2603664).

Almost surely, 2^20581247 is an apocalyptic number.

20581247 is a deficient number, since it is larger than the sum of its proper divisors (248065).

20581247 is a wasteful number, since it uses less digits than its factorization.

20581247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 20581247 is about 4536.6559270017. The cubic root of 20581247 is about 274.0462697360.

Adding to 20581247 its reverse (74218502), we get a palindrome (94799749).

The spelling of 20581247 in words is "twenty million, five hundred eighty-one thousand, two hundred forty-seven".