21101345 has 4 divisors (see below), whose sum is σ = 25321620. Its totient is φ = 16881072.

The previous prime is 21101341. The next prime is 21101371. The reversal of 21101345 is 54310112.

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 13075456 + 8025889 = 3616^2 + 2833^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101345 - 2² = 21101341 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21101341) 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, 2110130 + ... + 2110139.

It is an arithmetic number, because the mean of its divisors is an integer number (6330405).

Almost surely, 2^21101345 is an apocalyptic number.

It is an amenable number.

21101345 is a deficient number, since it is larger than the sum of its proper divisors (4220275).

21101345 is an equidigital number, since it uses as much as digits as its factorization.

21101345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4220274.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21101345 is about 4593.6200321751. The cubic root of 21101345 is about 276.3355201601.

Adding to 21101345 its reverse (54310112), we get a palindrome (75411457).

The spelling of 21101345 in words is "twenty-one million, one hundred one thousand, three hundred forty-five".