21105950623 has 16 divisors (see below), whose sum is σ = 21701661696. Its totient is φ = 20515249440.

The previous prime is 21105950587. The next prime is 21105950683. The reversal of 21105950623 is 32605950112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21105950623 is a prime.

It is a super-3 number, since 3×21105950623³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105950683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13332090 + ... + 13333672.

It is an arithmetic number, because the mean of its divisors is an integer number (1356353856).

Almost surely, 2^21105950623 is an apocalyptic number.

21105950623 is a deficient number, since it is larger than the sum of its proper divisors (595711073).

21105950623 is a wasteful number, since it uses less digits than its factorization.

21105950623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2934.

The product of its (nonzero) digits is 16200, while the sum is 34.

The spelling of 21105950623 in words is "twenty-one billion, one hundred five million, nine hundred fifty thousand, six hundred twenty-three".