20781771265 has 16 divisors (see below), whose sum is σ = 26345459520. Its totient is φ = 15693514560.

The previous prime is 20781771259. The next prime is 20781771281. The reversal of 20781771265 is 56217718702.

It is not a de Polignac number, because 20781771265 - 2⁷ = 20781771137 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 368551 + ... + 421180.

It is an arithmetic number, because the mean of its divisors is an integer number (1646591220).

Almost surely, 2^20781771265 is an apocalyptic number.

It is an amenable number.

20781771265 is a deficient number, since it is larger than the sum of its proper divisors (5563688255).

20781771265 is a wasteful number, since it uses less digits than its factorization.

20781771265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790032.

The product of its (nonzero) digits is 329280, while the sum is 46.

The spelling of 20781771265 in words is "twenty billion, seven hundred eighty-one million, seven hundred seventy-one thousand, two hundred sixty-five".