11661997349520 has 1120 divisors, whose sum is σ = 47568687409152. Its totient is φ = 2602500046848.

The previous prime is 11661997349449. The next prime is 11661997349521. The reversal of 11661997349520 is 2594379916611.

11661997349520 is a `hidden beast` number, since 1 + 1 + 6 + 6 + 19 + 97 + 3 + 4 + 9 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (11661997349521) by changing a digit.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 4824987352 + ... + 4824989768.

Almost surely, 2^{11661997349520} is an apocalyptic number.

11661997349520 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 11661997349520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23784343704576).

11661997349520 is an abundant number, since it is smaller than the sum of its proper divisors (35906690059632).

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

11661997349520 is a wasteful number, since it uses less digits than its factorization.

11661997349520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2731 (or 2710 counting only the distinct ones).

The product of its (nonzero) digits is 22044960, while the sum is 63.

The spelling of 11661997349520 in words is "eleven trillion, six hundred sixty-one billion, nine hundred ninety-seven million, three hundred forty-nine thousand, five hundred twenty".