21340577 has 4 divisors (see below), whose sum is σ = 21420180. Its totient is φ = 21260976.

The previous prime is 21340567. The next prime is 21340597. The reversal of 21340577 is 77504312.

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 4946176 + 16394401 = 2224^2 + 4049^2 .

It is a cyclic number.

It is not a de Polignac number, because 21340577 - 2¹⁰ = 21339553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21340537) 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, 39398 + ... + 39935.

It is an arithmetic number, because the mean of its divisors is an integer number (5355045).

Almost surely, 2^21340577 is an apocalyptic number.

It is an amenable number.

21340577 is a deficient number, since it is larger than the sum of its proper divisors (79603).

21340577 is an equidigital number, since it uses as much as digits as its factorization.

21340577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79602.

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

The square root of 21340577 is about 4619.5862368831. The cubic root of 21340577 is about 277.3758966753.

Adding to 21340577 its reverse (77504312), we get a palindrome (98844889).

The spelling of 21340577 in words is "twenty-one million, three hundred forty thousand, five hundred seventy-seven".