20781029 has 8 divisors (see below), whose sum is σ = 21960960. Its totient is φ = 19624176.

The previous prime is 20781017. The next prime is 20781031. The reversal of 20781029 is 92018702.

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 20781029 - 2¹⁶ = 20715493 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20780992 and 20781010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20781049) 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, 3902 + ... + 7535.

It is an arithmetic number, because the mean of its divisors is an integer number (2745120).

Almost surely, 2^20781029 is an apocalyptic number.

It is an amenable number.

20781029 is a deficient number, since it is larger than the sum of its proper divisors (1179931).

20781029 is a wasteful number, since it uses less digits than its factorization.

20781029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11539.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20781029 is about 4558.6213924826. The cubic root of 20781029 is about 274.9301376252.

The spelling of 20781029 in words is "twenty million, seven hundred eighty-one thousand, twenty-nine".