20781070 has 8 divisors (see below), whose sum is σ = 37405944. Its totient is φ = 8312424.

The previous prime is 20781049. The next prime is 20781071. The reversal of 20781070 is 7018702.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20781071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1039044 + ... + 1039063.

It is an arithmetic number, because the mean of its divisors is an integer number (4675743).

Almost surely, 2^20781070 is an apocalyptic number.

20781070 is a deficient number, since it is larger than the sum of its proper divisors (16624874).

20781070 is a wasteful number, since it uses less digits than its factorization.

20781070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2078114.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 20781070 is about 4558.6258894540. The cubic root of 20781070 is about 274.9303184332.

Adding to 20781070 its reverse (7018702), we get a palindrome (27799772).

The spelling of 20781070 in words is "twenty million, seven hundred eighty-one thousand, seventy".