21131617347 has 12 divisors (see below), whose sum is σ = 30527826264. Its totient is φ = 14085723840.

The previous prime is 21131617343. The next prime is 21131617349. The reversal of 21131617347 is 74371613112.

It is a happy number.

21131617347 is a `hidden beast` number, since 2 + 1 + 1 + 3 + 1 + 617 + 34 + 7 = 666.

It is not a de Polignac number, because 21131617347 - 2² = 21131617343 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21131617343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 100773 + ... + 228950.

It is an arithmetic number, because the mean of its divisors is an integer number (2543985522).

Almost surely, 2^21131617347 is an apocalyptic number.

21131617347 is a deficient number, since it is larger than the sum of its proper divisors (9396208917).

21131617347 is a wasteful number, since it uses less digits than its factorization.

21131617347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336850 (or 336847 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The spelling of 21131617347 in words is "twenty-one billion, one hundred thirty-one million, six hundred seventeen thousand, three hundred forty-seven".