20781013 has 8 divisors (see below), whose sum is σ = 23283360. Its totient is φ = 18380880.

The previous prime is 20780999. The next prime is 20781017. The reversal of 20781013 is 31018702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20781013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20781017) 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, 25123 + ... + 25936.

It is an arithmetic number, because the mean of its divisors is an integer number (2910420).

Almost surely, 2^20781013 is an apocalyptic number.

It is an amenable number.

20781013 is a deficient number, since it is larger than the sum of its proper divisors (2502347).

20781013 is a wasteful number, since it uses less digits than its factorization.

20781013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51107.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 20781013 is about 4558.6196375657. The cubic root of 20781013 is about 274.9300670659.

Adding to 20781013 its reverse (31018702), we get a palindrome (51799715).

The spelling of 20781013 in words is "twenty million, seven hundred eighty-one thousand, thirteen".