21461545 has 32 divisors (see below), whose sum is σ = 31564800. Its totient is φ = 13680576.

The previous prime is 21461543. The next prime is 21461551. The reversal of 21461545 is 54516412.

It is not a de Polignac number, because 21461545 - 2¹ = 21461543 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21461543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38962 + ... + 39508.

It is an arithmetic number, because the mean of its divisors is an integer number (986400).

Almost surely, 2^21461545 is an apocalyptic number.

It is an amenable number.

21461545 is a deficient number, since it is larger than the sum of its proper divisors (10103255).

21461545 is a wasteful number, since it uses less digits than its factorization.

21461545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637.

The product of its digits is 4800, while the sum is 28.

The square root of 21461545 is about 4632.6606825884. The cubic root of 21461545 is about 277.8990066703.

Adding to 21461545 its reverse (54516412), we get a palindrome (75977957).

The spelling of 21461545 in words is "twenty-one million, four hundred sixty-one thousand, five hundred forty-five".