21145611 has 16 divisors (see below), whose sum is σ = 29959200. Its totient is φ = 13241088.

The previous prime is 21145601. The next prime is 21145639. The reversal of 21145611 is 11654112.

It is not a de Polignac number, because 21145611 - 2⁷ = 21145483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21145601) 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, 66 + ... + 6503.

It is an arithmetic number, because the mean of its divisors is an integer number (1872450).

Almost surely, 2^21145611 is an apocalyptic number.

21145611 is a deficient number, since it is larger than the sum of its proper divisors (8813589).

21145611 is a wasteful number, since it uses less digits than its factorization.

21145611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6638.

The product of its digits is 240, while the sum is 21.

The square root of 21145611 is about 4598.4357122830. The cubic root of 21145611 is about 276.5286156642.

Adding to 21145611 its reverse (11654112), we get a palindrome (32799723).

The spelling of 21145611 in words is "twenty-one million, one hundred forty-five thousand, six hundred eleven".