21436073 has 4 divisors (see below), whose sum is σ = 21463380. Its totient is φ = 21408768.

The previous prime is 21436067. The next prime is 21436087. The reversal of 21436073 is 37063412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19254544 + 2181529 = 4388^2 + 1477^2 .

It is a cyclic number.

It is not a de Polignac number, because 21436073 - 2¹⁰ = 21435049 is a prime.

It is a super-2 number, since 2×21436073² = 919010451322658, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21436013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12440 + ... + 14057.

It is an arithmetic number, because the mean of its divisors is an integer number (5365845).

Almost surely, 2^21436073 is an apocalyptic number.

It is an amenable number.

21436073 is a deficient number, since it is larger than the sum of its proper divisors (27307).

21436073 is an equidigital number, since it uses as much as digits as its factorization.

21436073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27306.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 21436073 is about 4629.9106902833. The cubic root of 21436073 is about 277.7890200902.

Adding to 21436073 its reverse (37063412), we get a palindrome (58499485).

The spelling of 21436073 in words is "twenty-one million, four hundred thirty-six thousand, seventy-three".