21441657 has 4 divisors (see below), whose sum is σ = 28588880. Its totient is φ = 14294436.

The previous prime is 21441617. The next prime is 21441661. The reversal of 21441657 is 75614412.

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 not a de Polignac number, because 21441657 - 2²³ = 13053049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21441617) 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 3 ways as a sum of consecutive naturals, for example, 3573607 + ... + 3573612.

It is an arithmetic number, because the mean of its divisors is an integer number (7147220).

Almost surely, 2^21441657 is an apocalyptic number.

It is an amenable number.

21441657 is a deficient number, since it is larger than the sum of its proper divisors (7147223).

21441657 is an equidigital number, since it uses as much as digits as its factorization.

21441657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7147222.

The product of its digits is 6720, while the sum is 30.

The square root of 21441657 is about 4630.5136864067. The cubic root of 21441657 is about 277.8131389235.

The spelling of 21441657 in words is "twenty-one million, four hundred forty-one thousand, six hundred fifty-seven".