21532005 has 24 divisors (see below), whose sum is σ = 40716000. Its totient is φ = 10439520.

The previous prime is 21531989. The next prime is 21532019. The reversal of 21532005 is 50023512.

It is a happy number.

It is not a de Polignac number, because 21532005 - 2⁴ = 21531989 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 21255 + ... + 22244.

It is an arithmetic number, because the mean of its divisors is an integer number (1696500).

Almost surely, 2^21532005 is an apocalyptic number.

It is an amenable number.

21532005 is a deficient number, since it is larger than the sum of its proper divisors (19183995).

21532005 is a wasteful number, since it uses less digits than its factorization.

21532005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43521 (or 43518 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21532005 is about 4640.2591522457. The cubic root of 21532005 is about 278.2027961473.

Adding to 21532005 its reverse (50023512), we get a palindrome (71555517).

The spelling of 21532005 in words is "twenty-one million, five hundred thirty-two thousand, five".