21520126 has 4 divisors (see below), whose sum is σ = 32280192. Its totient is φ = 10760062.

The previous prime is 21520091. The next prime is 21520133. The reversal of 21520126 is 62102512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5380030 + ... + 5380033.

It is an arithmetic number, because the mean of its divisors is an integer number (8070048).

Almost surely, 2^21520126 is an apocalyptic number.

21520126 is a deficient number, since it is larger than the sum of its proper divisors (10760066).

21520126 is a wasteful number, since it uses less digits than its factorization.

21520126 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10760065.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21520126 is about 4638.9789824917. The cubic root of 21520126 is about 278.1516261341.

Adding to 21520126 its reverse (62102512), we get a palindrome (83622638).

The spelling of 21520126 in words is "twenty-one million, five hundred twenty thousand, one hundred twenty-six".