21771345 has 8 divisors (see below), whose sum is σ = 34834176. Its totient is φ = 11611376.

The previous prime is 21771329. The next prime is 21771353. The reversal of 21771345 is 54317712.

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 21771345 - 2⁴ = 21771329 is a prime.

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, 725697 + ... + 725726.

It is an arithmetic number, because the mean of its divisors is an integer number (4354272).

Almost surely, 2^21771345 is an apocalyptic number.

It is an amenable number.

21771345 is a deficient number, since it is larger than the sum of its proper divisors (13062831).

21771345 is a wasteful number, since it uses less digits than its factorization.

21771345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1451431.

The product of its digits is 5880, while the sum is 30.

The square root of 21771345 is about 4665.9773895723. The cubic root of 21771345 is about 279.2297923138.

The spelling of 21771345 in words is "twenty-one million, seven hundred seventy-one thousand, three hundred forty-five".