21570105 has 16 divisors (see below), whose sum is σ = 35098560. Its totient is φ = 11308608.

The previous prime is 21570103. The next prime is 21570137. The reversal of 21570105 is 50107512.

It is not a de Polignac number, because 21570105 - 2¹ = 21570103 is a prime.

It is a super-2 number, since 2×21570105² = 930538859422050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21570103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11302 + ... + 13071.

It is an arithmetic number, because the mean of its divisors is an integer number (2193660).

Almost surely, 2^21570105 is an apocalyptic number.

It is an amenable number.

21570105 is a deficient number, since it is larger than the sum of its proper divisors (13528455).

21570105 is a wasteful number, since it uses less digits than its factorization.

21570105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24440.

The product of its (nonzero) digits is 350, while the sum is 21.

The square root of 21570105 is about 4644.3627119337. The cubic root of 21570105 is about 278.3667889395.

Adding to 21570105 its reverse (50107512), we get a palindrome (71677617).

The spelling of 21570105 in words is "twenty-one million, five hundred seventy thousand, one hundred five".