11909721600 has 720 divisors, whose sum is σ = 50606844288. Its totient is φ = 2717245440.

The previous prime is 11909721599. The next prime is 11909721601. The reversal of 11909721600 is 612790911.

It is an interprime number because it is at equal distance from previous prime (11909721599) and next prime (11909721601).

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11909721601) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 21772527 + ... + 21773073.

Almost surely, 2^11909721600 is an apocalyptic number.

11909721600 is a gapful number since it is divisible by the number (10) 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 11909721600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25303422144).

11909721600 is an abundant number, since it is smaller than the sum of its proper divisors (38697122688).

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

11909721600 is an frugal number, since it uses more digits than its factorization.

11909721600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597 (or 564 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 36.

The spelling of 11909721600 in words is "eleven billion, nine hundred nine million, seven hundred twenty-one thousand, six hundred".