21355705 has 8 divisors (see below), whose sum is σ = 29287872. Its totient is φ = 14643888.

The previous prime is 21355693. The next prime is 21355717. The reversal of 21355705 is 50755312.

It is an interprime number because it is at equal distance from previous prime (21355693) and next prime (21355717).

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

It is not a de Polignac number, because 21355705 - 2⁷ = 21355577 is a prime.

It is a super-2 number, since 2×21355705² = 912132272094050, which contains 22 as substring.

It is a Duffinian 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, 305047 + ... + 305116.

It is an arithmetic number, because the mean of its divisors is an integer number (3660984).

Almost surely, 2^21355705 is an apocalyptic number.

It is an amenable number.

21355705 is a deficient number, since it is larger than the sum of its proper divisors (7932167).

21355705 is an equidigital number, since it uses as much as digits as its factorization.

21355705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610175.

The product of its (nonzero) digits is 5250, while the sum is 28.

The square root of 21355705 is about 4621.2233228876. The cubic root of 21355705 is about 277.4414236669.

The spelling of 21355705 in words is "twenty-one million, three hundred fifty-five thousand, seven hundred five".