21141564 has 12 divisors (see below), whose sum is σ = 49330344. Its totient is φ = 7047184.

The previous prime is 21141559. The next prime is 21141569. The reversal of 21141564 is 46514112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21141559) and next prime (21141569).

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21141569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 880887 + ... + 880910.

It is an arithmetic number, because the mean of its divisors is an integer number (4110862).

Almost surely, 2^21141564 is an apocalyptic number.

It is an amenable number.

21141564 is an abundant number, since it is smaller than the sum of its proper divisors (28188780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21141564 is a wasteful number, since it uses less digits than its factorization.

21141564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1761804 (or 1761802 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

The square root of 21141564 is about 4597.9956502807. The cubic root of 21141564 is about 276.5109731897.

Adding to 21141564 its reverse (46514112), we get a palindrome (67655676).

The spelling of 21141564 in words is "twenty-one million, one hundred forty-one thousand, five hundred sixty-four".