21311981297 has 8 divisors (see below), whose sum is σ = 21575828736. Its totient is φ = 21048302512.

The previous prime is 21311981287. The next prime is 21311981311. The reversal of 21311981297 is 79218911312.

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

It is a cyclic number.

It is not a de Polignac number, because 21311981297 - 2⁶ = 21311981233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21311981287) 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, 222323 + ... + 303399.

It is an arithmetic number, because the mean of its divisors is an integer number (2696978592).

Almost surely, 2^21311981297 is an apocalyptic number.

It is an amenable number.

21311981297 is a deficient number, since it is larger than the sum of its proper divisors (263847439).

21311981297 is an equidigital number, since it uses as much as digits as its factorization.

21311981297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84327.

The product of its digits is 54432, while the sum is 44.

The spelling of 21311981297 in words is "twenty-one billion, three hundred eleven million, nine hundred eighty-one thousand, two hundred ninety-seven".