21861093 has 16 divisors (see below), whose sum is σ = 29931840. Its totient is φ = 14187264.

The previous prime is 21861083. The next prime is 21861097. The reversal of 21861093 is 39016812.

It is not a de Polignac number, because 21861093 - 2⁵ = 21861061 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21861093.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21861097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19455 + ... + 20547.

It is an arithmetic number, because the mean of its divisors is an integer number (1870740).

Almost surely, 2^21861093 is an apocalyptic number.

It is an amenable number.

21861093 is a deficient number, since it is larger than the sum of its proper divisors (8070747).

21861093 is a wasteful number, since it uses less digits than its factorization.

21861093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1268.

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

The square root of 21861093 is about 4675.5847762606. The cubic root of 21861093 is about 279.6129558815.

The spelling of 21861093 in words is "twenty-one million, eight hundred sixty-one thousand, ninety-three".