11781601997 has 8 divisors (see below), whose sum is σ = 12855989952. Its totient is φ = 10707769600.

The previous prime is 11781601991. The next prime is 11781602003. The reversal of 11781601997 is 79910618711.

It is an interprime number because it is at equal distance from previous prime (11781601991) and next prime (11781602003).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 11781601997 - 2⁶ = 11781601933 is a prime.

It is a super-2 number, since 2×11781601997² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11781601991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93908 + ... + 179949.

It is an arithmetic number, because the mean of its divisors is an integer number (1606998744).

Almost surely, 2^11781601997 is an apocalyptic number.

It is an amenable number.

11781601997 is a deficient number, since it is larger than the sum of its proper divisors (1074387955).

11781601997 is a wasteful number, since it uses less digits than its factorization.

11781601997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277779.

The product of its (nonzero) digits is 190512, while the sum is 50.

The spelling of 11781601997 in words is "eleven billion, seven hundred eighty-one million, six hundred one thousand, nine hundred ninety-seven".