21621166311 has 8 divisors (see below), whose sum is σ = 29822298480. Its totient is φ = 13917072512.

The previous prime is 21621166283. The next prime is 21621166313. The reversal of 21621166311 is 11366112612.

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 a de Polignac number, because none of the positive numbers 2^k-21621166311 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621166313) 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, 124259490 + ... + 124259663.

It is an arithmetic number, because the mean of its divisors is an integer number (3727787310).

Almost surely, 2^21621166311 is an apocalyptic number.

21621166311 is a deficient number, since it is larger than the sum of its proper divisors (8201132169).

21621166311 is a wasteful number, since it uses less digits than its factorization.

21621166311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248519185.

The product of its digits is 2592, while the sum is 30.

Adding to 21621166311 its reverse (11366112612), we get a palindrome (32987278923).

The spelling of 21621166311 in words is "twenty-one billion, six hundred twenty-one million, one hundred sixty-six thousand, three hundred eleven".