20909451646 has 24 divisors (see below), whose sum is σ = 32528212704. Its totient is φ = 10080168000.

The previous prime is 20909451643. The next prime is 20909451659. The reversal of 20909451646 is 64615490902.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20909451596 and 20909451605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20909451643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1254906 + ... + 1271458.

It is an arithmetic number, because the mean of its divisors is an integer number (1355342196).

Almost surely, 2^20909451646 is an apocalyptic number.

20909451646 is a deficient number, since it is larger than the sum of its proper divisors (11618761058).

20909451646 is a wasteful number, since it uses less digits than its factorization.

20909451646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17364 (or 17335 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 46.

The spelling of 20909451646 in words is "twenty billion, nine hundred nine million, four hundred fifty-one thousand, six hundred forty-six".