21537086 has 4 divisors (see below), whose sum is σ = 32305632. Its totient is φ = 10768542.

The previous prime is 21537073. The next prime is 21537091. The reversal of 21537086 is 68073512.

It is a happy number.

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5384270 + ... + 5384273.

It is an arithmetic number, because the mean of its divisors is an integer number (8076408).

Almost surely, 2^21537086 is an apocalyptic number.

21537086 is a deficient number, since it is larger than the sum of its proper divisors (10768546).

21537086 is a wasteful number, since it uses less digits than its factorization.

21537086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10768545.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21537086 is about 4640.8066109244. The cubic root of 21537086 is about 278.2246773304.

The spelling of 21537086 in words is "twenty-one million, five hundred thirty-seven thousand, eighty-six".