21312155441 has 8 divisors (see below), whose sum is σ = 21516915264. Its totient is φ = 21108269520.

The previous prime is 21312155393. The next prime is 21312155443. The reversal of 21312155441 is 14455121312.

It is a happy number.

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 21312155441 - 2¹⁰ = 21312154417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312155443) 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, 169415 + ... + 267068.

It is an arithmetic number, because the mean of its divisors is an integer number (2689614408).

Almost surely, 2^21312155441 is an apocalyptic number.

It is an amenable number.

21312155441 is a deficient number, since it is larger than the sum of its proper divisors (204759823).

21312155441 is a wasteful number, since it uses less digits than its factorization.

21312155441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436951.

The product of its digits is 4800, while the sum is 29.

Adding to 21312155441 its reverse (14455121312), we get a palindrome (35767276753).

The spelling of 21312155441 in words is "twenty-one billion, three hundred twelve million, one hundred fifty-five thousand, four hundred forty-one".