21150705 has 32 divisors (see below), whose sum is σ = 36403200. Its totient is φ = 10452672.

The previous prime is 21150683. The next prime is 21150709. The reversal of 21150705 is 50705112.

It is not a de Polignac number, because 21150705 - 2⁵ = 21150673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21150709) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12606 + ... + 14184.

It is an arithmetic number, because the mean of its divisors is an integer number (1137600).

Almost surely, 2^21150705 is an apocalyptic number.

It is an amenable number.

21150705 is a deficient number, since it is larger than the sum of its proper divisors (15252495).

21150705 is a wasteful number, since it uses less digits than its factorization.

21150705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1653.

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

The square root of 21150705 is about 4598.9895629366. The cubic root of 21150705 is about 276.5508192264.

Adding to 21150705 its reverse (50705112), we get a palindrome (71855817).

The spelling of 21150705 in words is "twenty-one million, one hundred fifty thousand, seven hundred five".