21390266881 has 8 divisors (see below), whose sum is σ = 23175228384. Its totient is φ = 19663828800.

The previous prime is 21390266851. The next prime is 21390266927. The reversal of 21390266881 is 18866209312.

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 21390266881 - 2¹⁹ = 21389742593 is a prime.

It is a super-2 number, since 2×21390266881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21390266851) 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 7 ways as a sum of consecutive naturals, for example, 14630095 + ... + 14631556.

It is an arithmetic number, because the mean of its divisors is an integer number (2896903548).

Almost surely, 2^21390266881 is an apocalyptic number.

It is an amenable number.

21390266881 is a deficient number, since it is larger than the sum of its proper divisors (1784961503).

21390266881 is a wasteful number, since it uses less digits than its factorization.

21390266881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29261711.

The product of its (nonzero) digits is 248832, while the sum is 46.

The spelling of 21390266881 in words is "twenty-one billion, three hundred ninety million, two hundred sixty-six thousand, eight hundred eighty-one".