21561485 has 32 divisors (see below), whose sum is σ = 30412800. Its totient is φ = 14506560.

The previous prime is 21561481. The next prime is 21561497. The reversal of 21561485 is 58416512.

It is not a de Polignac number, because 21561485 - 2² = 21561481 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561481) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48896 + ... + 49334.

It is an arithmetic number, because the mean of its divisors is an integer number (950400).

Almost surely, 2^21561485 is an apocalyptic number.

It is an amenable number.

21561485 is a deficient number, since it is larger than the sum of its proper divisors (8851315).

21561485 is a wasteful number, since it uses less digits than its factorization.

21561485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521.

The product of its digits is 9600, while the sum is 32.

The square root of 21561485 is about 4643.4346124394. The cubic root of 21561485 is about 278.3297030216.

Adding to 21561485 its reverse (58416512), we get a palindrome (79977997).

The spelling of 21561485 in words is "twenty-one million, five hundred sixty-one thousand, four hundred eighty-five".