21488545 has 16 divisors (see below), whose sum is σ = 27885312. Its totient is φ = 15802560.

The previous prime is 21488543. The next prime is 21488557. The reversal of 21488545 is 54588412.

It is not a de Polignac number, because 21488545 - 2¹ = 21488543 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21488543) 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 15 ways as a sum of consecutive naturals, for example, 19684 + ... + 20746.

It is an arithmetic number, because the mean of its divisors is an integer number (1742832).

Almost surely, 2^21488545 is an apocalyptic number.

It is an amenable number.

21488545 is a deficient number, since it is larger than the sum of its proper divisors (6396767).

21488545 is a wasteful number, since it uses less digits than its factorization.

21488545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392.

The product of its digits is 51200, while the sum is 37.

The square root of 21488545 is about 4635.5738587579. The cubic root of 21488545 is about 278.0154960912.

It can be divided in two parts, 21 and 488545, that added together give a triangular number (488566 = T₉₈₈).

The spelling of 21488545 in words is "twenty-one million, four hundred eighty-eight thousand, five hundred forty-five".