21534001 has 4 divisors (see below), whose sum is σ = 21855472. Its totient is φ = 21212532.

The previous prime is 21533999. The next prime is 21534031. The reversal of 21534001 is 10043512.

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 21534001 - 2¹ = 21533999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21534031) 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, 160635 + ... + 160768.

It is an arithmetic number, because the mean of its divisors is an integer number (5463868).

Almost surely, 2^21534001 is an apocalyptic number.

It is an amenable number.

21534001 is a deficient number, since it is larger than the sum of its proper divisors (321471).

21534001 is an equidigital number, since it uses as much as digits as its factorization.

21534001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321470.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21534001 is about 4640.4742214563. The cubic root of 21534001 is about 278.2113922755.

Adding to 21534001 its reverse (10043512), we get a palindrome (31577513).

The spelling of 21534001 in words is "twenty-one million, five hundred thirty-four thousand, one".