21770345 has 8 divisors (see below), whose sum is σ = 26174664. Its totient is φ = 17382784.

The previous prime is 21770323. The next prime is 21770363. The reversal of 21770345 is 54307712.

It can be written as a sum of positive squares in 4 ways, for example, as 1771561 + 19998784 = 1331^2 + 4472^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21770345 - 2¹⁴ = 21753961 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1124 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (3271833).

Almost surely, 2^21770345 is an apocalyptic number.

It is an amenable number.

21770345 is a deficient number, since it is larger than the sum of its proper divisors (4404319).

21770345 is an equidigital number, since it uses as much as digits as its factorization.

21770345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8379.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 21770345 is about 4665.8702296571. The cubic root of 21770345 is about 279.2255170601.

The spelling of 21770345 in words is "twenty-one million, seven hundred seventy thousand, three hundred forty-five".