21900105 has 32 divisors (see below), whose sum is σ = 40197120. Its totient is φ = 11301120.

The previous prime is 21900091. The next prime is 21900107. The reversal of 21900105 is 50100912.

It is not a de Polignac number, because 21900105 - 2¹⁵ = 21867337 is a prime.

It is a super-2 number, since 2×21900105² = 959229198022050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21900107) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1569 + ... + 6801.

It is an arithmetic number, because the mean of its divisors is an integer number (1256160).

Almost surely, 2^21900105 is an apocalyptic number.

It is an amenable number.

21900105 is a deficient number, since it is larger than the sum of its proper divisors (18297015).

21900105 is a wasteful number, since it uses less digits than its factorization.

21900105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5278 (or 5272 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 21900105 is about 4679.7548012690. The cubic root of 21900105 is about 279.7791838970.

The spelling of 21900105 in words is "twenty-one million, nine hundred thousand, one hundred five".