20693640987 has 6 divisors (see below), whose sum is σ = 29890814772. Its totient is φ = 13795760652.

The previous prime is 20693640977. The next prime is 20693641027. The reversal of 20693640987 is 78904639602.

It is a happy number.

It is not a de Polignac number, because 20693640987 - 2¹¹ = 20693638939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20693640907) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1149646713 + ... + 1149646730.

It is an arithmetic number, because the mean of its divisors is an integer number (4981802462).

Almost surely, 2^20693640987 is an apocalyptic number.

20693640987 is a deficient number, since it is larger than the sum of its proper divisors (9197173785).

20693640987 is a wasteful number, since it uses less digits than its factorization.

20693640987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2299293449 (or 2299293446 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 54.

The spelling of 20693640987 in words is "twenty billion, six hundred ninety-three million, six hundred forty thousand, nine hundred eighty-seven".