21361610 has 16 divisors (see below), whose sum is σ = 39026016. Its totient is φ = 8416848.

The previous prime is 21361609. The next prime is 21361619. The reversal of 21361610 is 1616312.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21361619) 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, 15272 + ... + 16611.

It is an arithmetic number, because the mean of its divisors is an integer number (2439126).

Almost surely, 2^21361610 is an apocalyptic number.

21361610 is a deficient number, since it is larger than the sum of its proper divisors (17664406).

21361610 is a wasteful number, since it uses less digits than its factorization.

21361610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31957.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21361610 is about 4621.8621788193. The cubic root of 21361610 is about 277.4669928006.

Adding to 21361610 its reverse (1616312), we get a palindrome (22977922).

The spelling of 21361610 in words is "twenty-one million, three hundred sixty-one thousand, six hundred ten".