20781650 has 48 divisors (see below), whose sum is σ = 42747264. Its totient is φ = 7476480.

The previous prime is 20781643. The next prime is 20781653. The reversal of 20781650 is 5618702.

It is not an unprimeable number, because it can be changed into a prime (20781653) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19019 + ... + 20081.

It is an arithmetic number, because the mean of its divisors is an integer number (890568).

Almost surely, 2^20781650 is an apocalyptic number.

20781650 is an abundant number, since it is smaller than the sum of its proper divisors (21965614).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20781650 is a wasteful number, since it uses less digits than its factorization.

20781650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1115 (or 1110 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 20781650 is about 4558.6895046713. The cubic root of 20781650 is about 274.9328761793.

The spelling of 20781650 in words is "twenty million, seven hundred eighty-one thousand, six hundred fifty".