20649456861 has 64 divisors (see below), whose sum is σ = 34255457280. Its totient is φ = 10898979840.

The previous prime is 20649456847. The next prime is 20649456869. The reversal of 20649456861 is 16865494602.

It is not a de Polignac number, because 20649456861 - 2¹³ = 20649448669 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20649456869) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 435811 + ... + 480863.

It is an arithmetic number, because the mean of its divisors is an integer number (535241520).

Almost surely, 2^20649456861 is an apocalyptic number.

It is an amenable number.

20649456861 is a deficient number, since it is larger than the sum of its proper divisors (13606000419).

20649456861 is a wasteful number, since it uses less digits than its factorization.

20649456861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45146.

The product of its (nonzero) digits is 2488320, while the sum is 51.

The spelling of 20649456861 in words is "twenty billion, six hundred forty-nine million, four hundred fifty-six thousand, eight hundred sixty-one".