21140645 has 8 divisors (see below), whose sum is σ = 25431840. Its totient is φ = 16870480.

The previous prime is 21140633. The next prime is 21140663. The reversal of 21140645 is 54604112.

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

It is not a de Polignac number, because 21140645 - 2⁸ = 21140389 is a prime.

It is a super-3 number, since 3×21140645³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21140645.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2951 + ... + 7140.

It is an arithmetic number, because the mean of its divisors is an integer number (3178980).

Almost surely, 2^21140645 is an apocalyptic number.

It is an amenable number.

21140645 is a deficient number, since it is larger than the sum of its proper divisors (4291195).

21140645 is a wasteful number, since it uses less digits than its factorization.

21140645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10515.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21140645 is about 4597.8957143459. The cubic root of 21140645 is about 276.5069665913.

Adding to 21140645 its reverse (54604112), we get a palindrome (75744757).

The spelling of 21140645 in words is "twenty-one million, one hundred forty thousand, six hundred forty-five".