21545049 has 16 divisors (see below), whose sum is σ = 29715840. Its totient is φ = 13875840.

The previous prime is 21545047. The next prime is 21545059. The reversal of 21545049 is 94054512.

It is not a de Polignac number, because 21545049 - 2¹ = 21545047 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21545047) 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, 12604 + ... + 14210.

It is an arithmetic number, because the mean of its divisors is an integer number (1857240).

Almost surely, 2^21545049 is an apocalyptic number.

It is an amenable number.

21545049 is a deficient number, since it is larger than the sum of its proper divisors (8170791).

21545049 is a wasteful number, since it uses less digits than its factorization.

21545049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 21545049 is about 4641.6644643921. The cubic root of 21545049 is about 278.2589628432.

The spelling of 21545049 in words is "twenty-one million, five hundred forty-five thousand, forty-nine".