21562081 has 8 divisors (see below), whose sum is σ = 22636800. Its totient is φ = 20511120.

The previous prime is 21562067. The next prime is 21562117. The reversal of 21562081 is 18026512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21562081 is a prime.

It is a super-2 number, since 2×21562081² = 929846674101122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21562031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4066 + ... + 7723.

It is an arithmetic number, because the mean of its divisors is an integer number (2829600).

Almost surely, 2^21562081 is an apocalyptic number.

It is an amenable number.

21562081 is a deficient number, since it is larger than the sum of its proper divisors (1074719).

21562081 is a wasteful number, since it uses less digits than its factorization.

21562081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11879.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21562081 is about 4643.4987886291. The cubic root of 21562081 is about 278.3322675168.

Adding to 21562081 its reverse (18026512), we get a palindrome (39588593).

The spelling of 21562081 in words is "twenty-one million, five hundred sixty-two thousand, eighty-one".