21508070 has 16 divisors (see below), whose sum is σ = 39078288. Its totient is φ = 8522400.

The previous prime is 21508061. The next prime is 21508087. The reversal of 21508070 is 7080512.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8981 + ... + 11120.

It is an arithmetic number, because the mean of its divisors is an integer number (2442393).

Almost surely, 2^21508070 is an apocalyptic number.

21508070 is a deficient number, since it is larger than the sum of its proper divisors (17570218).

21508070 is a wasteful number, since it uses less digits than its factorization.

21508070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20215.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 21508070 is about 4637.6793765848. The cubic root of 21508070 is about 278.0996744183.

Adding to 21508070 its reverse (7080512), we get a palindrome (28588582).

The spelling of 21508070 in words is "twenty-one million, five hundred eight thousand, seventy".