209096691989640 has 768 divisors, whose sum is σ = 797188706979840. Its totient is φ = 43480200960000.

The previous prime is 209096691989629. The next prime is 209096691989651. The reversal of 209096691989640 is 46989196690902.

It is an interprime number because it is at equal distance from previous prime (209096691989629) and next prime (209096691989651).

It is a Harshad number since it is a multiple of its sum of digits (78).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 21225930715 + ... + 21225940565.

It is an arithmetic number, because the mean of its divisors is an integer number (1038006128880).

Almost surely, 2^{209096691989640} is an apocalyptic number.

209096691989640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209096691989640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (398594353489920).

209096691989640 is an abundant number, since it is smaller than the sum of its proper divisors (588092014990200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209096691989640 is a wasteful number, since it uses less digits than its factorization.

209096691989640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13874 (or 13863 counting only the distinct ones).

The product of its (nonzero) digits is 816293376, while the sum is 78.

The spelling of 209096691989640 in words is "two hundred nine trillion, ninety-six billion, six hundred ninety-one million, nine hundred eighty-nine thousand, six hundred forty".