20781955659 has 16 divisors (see below), whose sum is σ = 27920424960. Its totient is φ = 13749126720.

The previous prime is 20781955657. The next prime is 20781955661. The reversal of 20781955659 is 95655918702.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20781955657) and next prime (20781955661).

It is not a de Polignac number, because 20781955659 - 2¹ = 20781955657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20781955599 and 20781955608.

It is not an unprimeable number, because it can be changed into a prime (20781955651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1749462 + ... + 1761300.

It is an arithmetic number, because the mean of its divisors is an integer number (1745026560).

Almost surely, 2^20781955659 is an apocalyptic number.

20781955659 is a deficient number, since it is larger than the sum of its proper divisors (7138469301).

20781955659 is a wasteful number, since it uses less digits than its factorization.

20781955659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16250.

The product of its (nonzero) digits is 6804000, while the sum is 57.

The spelling of 20781955659 in words is "twenty billion, seven hundred eighty-one million, nine hundred fifty-five thousand, six hundred fifty-nine".