21573036 has 18 divisors (see below), whose sum is σ = 54531932. Its totient is φ = 7191000.

The previous prime is 21573031. The next prime is 21573049. The reversal of 21573036 is 63037512.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (21573031) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 299590 + ... + 299661.

Almost surely, 2^21573036 is an apocalyptic number.

It is an amenable number.

21573036 is an abundant number, since it is smaller than the sum of its proper divisors (32958896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21573036 is a wasteful number, since it uses less digits than its factorization.

21573036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599261 (or 599256 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The square root of 21573036 is about 4644.6782450456. The cubic root of 21573036 is about 278.3793967610.

The spelling of 21573036 in words is "twenty-one million, five hundred seventy-three thousand, thirty-six".