21249345 has 16 divisors (see below), whose sum is σ = 36614592. Its totient is φ = 10461120.

The previous prime is 21249331. The next prime is 21249443. The reversal of 21249345 is 54394212.

It is not a de Polignac number, because 21249345 - 2⁴ = 21249329 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54291 + ... + 54680.

It is an arithmetic number, because the mean of its divisors is an integer number (2288412).

Almost surely, 2^21249345 is an apocalyptic number.

It is an amenable number.

21249345 is a deficient number, since it is larger than the sum of its proper divisors (15365247).

21249345 is a wasteful number, since it uses less digits than its factorization.

21249345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108992.

The product of its digits is 8640, while the sum is 30.

The square root of 21249345 is about 4609.7011833740. The cubic root of 21249345 is about 276.9800669448.

The spelling of 21249345 in words is "twenty-one million, two hundred forty-nine thousand, three hundred forty-five".