21342705 has 16 divisors (see below), whose sum is σ = 34205760. Its totient is φ = 11363648.

The previous prime is 21342697. The next prime is 21342709. The reversal of 21342705 is 50724312.

It is a cyclic number.

It is not a de Polignac number, because 21342705 - 2³ = 21342697 is a prime.

It is a super-2 number, since 2×21342705² = 911022113434050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21342709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15994 + ... + 17276.

It is an arithmetic number, because the mean of its divisors is an integer number (2137860).

Almost surely, 2^21342705 is an apocalyptic number.

It is an amenable number.

21342705 is a deficient number, since it is larger than the sum of its proper divisors (12863055).

21342705 is a wasteful number, since it uses less digits than its factorization.

21342705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2400.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21342705 is about 4619.8165547996. The cubic root of 21342705 is about 277.3851159869.

The spelling of 21342705 in words is "twenty-one million, three hundred forty-two thousand, seven hundred five".