13021561 has 8 divisors (see below), whose sum is σ = 15228224. Its totient is φ = 10901520.

The previous prime is 13021549. The next prime is 13021573. The reversal of 13021561 is 16512031.

It is an interprime number because it is at equal distance from previous prime (13021549) and next prime (13021573).

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

It is not a de Polignac number, because 13021561 - 2⁵ = 13021529 is a prime.

It is a super-2 number, since 2×13021561² = 339122101753442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13021861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21330 + ... + 21931.

It is an arithmetic number, because the mean of its divisors is an integer number (1903528).

Almost surely, 2^13021561 is an apocalyptic number.

It is an amenable number.

13021561 is a deficient number, since it is larger than the sum of its proper divisors (2206663).

13021561 is an equidigital number, since it uses as much as digits as its factorization.

13021561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43311.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 13021561 is about 3608.5400094775. The cubic root of 13021561 is about 235.2633896061.

Adding to 13021561 its reverse (16512031), we get a palindrome (29533592).

The spelling of 13021561 in words is "thirteen million, twenty-one thousand, five hundred sixty-one".