21073547 has 4 divisors (see below), whose sum is σ = 22989336. Its totient is φ = 19157760.

The previous prime is 21073519. The next prime is 21073553. The reversal of 21073547 is 74537012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21073547 - 2¹⁰ = 21072523 is a prime.

It is a super-2 number, since 2×21073547² = 888188766322418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21073447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 957878 + ... + 957899.

It is an arithmetic number, because the mean of its divisors is an integer number (5747334).

Almost surely, 2^21073547 is an apocalyptic number.

21073547 is a deficient number, since it is larger than the sum of its proper divisors (1915789).

21073547 is a wasteful number, since it uses less digits than its factorization.

21073547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1915788.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 21073547 is about 4590.5933167729. The cubic root of 21073547 is about 276.2141226791.

The spelling of 21073547 in words is "twenty-one million, seventy-three thousand, five hundred forty-seven".