21342577 has 4 divisors (see below), whose sum is σ = 21838960. Its totient is φ = 20846196.

The previous prime is 21342557. The next prime is 21342583. The reversal of 21342577 is 77524312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21342577 - 2⁷ = 21342449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21342557) 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, 248127 + ... + 248212.

It is an arithmetic number, because the mean of its divisors is an integer number (5459740).

Almost surely, 2^21342577 is an apocalyptic number.

It is an amenable number.

21342577 is a deficient number, since it is larger than the sum of its proper divisors (496383).

21342577 is an equidigital number, since it uses as much as digits as its factorization.

21342577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496382.

The product of its digits is 11760, while the sum is 31.

The square root of 21342577 is about 4619.8027014149. The cubic root of 21342577 is about 277.3845614592.

Adding to 21342577 its reverse (77524312), we get a palindrome (98866889).

The spelling of 21342577 in words is "twenty-one million, three hundred forty-two thousand, five hundred seventy-seven".