21496645 has 4 divisors (see below), whose sum is σ = 25795980. Its totient is φ = 17197312.

The previous prime is 21496637. The next prime is 21496649. The reversal of 21496645 is 54669412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2989441 + 18507204 = 1729^2 + 4302^2 .

It is a cyclic number.

It is not a de Polignac number, because 21496645 - 2³ = 21496637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21496649) 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, 2149660 + ... + 2149669.

It is an arithmetic number, because the mean of its divisors is an integer number (6448995).

Almost surely, 2^21496645 is an apocalyptic number.

It is an amenable number.

21496645 is a deficient number, since it is larger than the sum of its proper divisors (4299335).

21496645 is an equidigital number, since it uses as much as digits as its factorization.

21496645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4299334.

The product of its digits is 51840, while the sum is 37.

The square root of 21496645 is about 4636.4474546791. The cubic root of 21496645 is about 278.0504238884.

The spelling of 21496645 in words is "twenty-one million, four hundred ninety-six thousand, six hundred forty-five".