20259509691 has 16 divisors (see below), whose sum is σ = 27201722400. Its totient is φ = 13411926528.

The previous prime is 20259509687. The next prime is 20259509693. The reversal of 20259509691 is 19690595202.

It is a happy number.

It is not a de Polignac number, because 20259509691 - 2² = 20259509687 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20259509691.

It is not an unprimeable number, because it can be changed into a prime (20259509693) 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, 792355 + ... + 817523.

It is an arithmetic number, because the mean of its divisors is an integer number (1700107650).

Almost surely, 2^20259509691 is an apocalyptic number.

20259509691 is a deficient number, since it is larger than the sum of its proper divisors (6942212709).

20259509691 is a wasteful number, since it uses less digits than its factorization.

20259509691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27038.

The product of its (nonzero) digits is 437400, while the sum is 48.

The spelling of 20259509691 in words is "twenty billion, two hundred fifty-nine million, five hundred nine thousand, six hundred ninety-one".