21261710 has 8 divisors (see below), whose sum is σ = 38271096. Its totient is φ = 8504680.

The previous prime is 21261707. The next prime is 21261767. The reversal of 21261710 is 1716212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a zygodrome in base 9.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1063076 + ... + 1063095.

It is an arithmetic number, because the mean of its divisors is an integer number (4783887).

Almost surely, 2^21261710 is an apocalyptic number.

21261710 is a deficient number, since it is larger than the sum of its proper divisors (17009386).

21261710 is a wasteful number, since it uses less digits than its factorization.

21261710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2126178.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21261710 is about 4611.0421815464. The cubic root of 21261710 is about 277.0337814544.

Adding to 21261710 its reverse (1716212), we get a palindrome (22977922).

The spelling of 21261710 in words is "twenty-one million, two hundred sixty-one thousand, seven hundred ten".