21361406 has 32 divisors (see below), whose sum is σ = 36315648. Its totient is φ = 9339840.

The previous prime is 21361397. The next prime is 21361421. The reversal of 21361406 is 60416312.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75341 + ... + 75623.

It is an arithmetic number, because the mean of its divisors is an integer number (1134864).

Almost surely, 2^21361406 is an apocalyptic number.

21361406 is a deficient number, since it is larger than the sum of its proper divisors (14954242).

21361406 is a wasteful number, since it uses less digits than its factorization.

21361406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21361406 is about 4621.8401097398. The cubic root of 21361406 is about 277.4661095425.

Adding to 21361406 its reverse (60416312), we get a palindrome (81777718).

The spelling of 21361406 in words is "twenty-one million, three hundred sixty-one thousand, four hundred six".