21413645 has 16 divisors (see below), whose sum is σ = 28244160. Its totient is φ = 15456000.

The previous prime is 21413641. The next prime is 21413647. The reversal of 21413645 is 54631412.

It is not a de Polignac number, because 21413645 - 2² = 21413641 is a prime.

It is a super-3 number, since 3×21413645³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21413641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6245 + ... + 9045.

It is an arithmetic number, because the mean of its divisors is an integer number (1765260).

Almost surely, 2^21413645 is an apocalyptic number.

It is an amenable number.

21413645 is a deficient number, since it is larger than the sum of its proper divisors (6830515).

21413645 is a wasteful number, since it uses less digits than its factorization.

21413645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2956.

The product of its digits is 2880, while the sum is 26.

The square root of 21413645 is about 4627.4879794549. The cubic root of 21413645 is about 277.6921051646.

The spelling of 21413645 in words is "twenty-one million, four hundred thirteen thousand, six hundred forty-five".