21573401 has 4 divisors (see below), whose sum is σ = 22075152. Its totient is φ = 21071652.

The previous prime is 21573371. The next prime is 21573407. The reversal of 21573401 is 10437512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21573401 - 2¹⁴ = 21557017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21573407) 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, 250811 + ... + 250896.

It is an arithmetic number, because the mean of its divisors is an integer number (5518788).

Almost surely, 2^21573401 is an apocalyptic number.

It is an amenable number.

21573401 is a deficient number, since it is larger than the sum of its proper divisors (501751).

21573401 is an equidigital number, since it uses as much as digits as its factorization.

21573401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501750.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21573401 is about 4644.7175371598. The cubic root of 21573401 is about 278.3809667442.

The spelling of 21573401 in words is "twenty-one million, five hundred seventy-three thousand, four hundred one".