21513086 has 8 divisors (see below), whose sum is σ = 36879600. Its totient is φ = 9219888.

The previous prime is 21513083. The next prime is 21513091. The reversal of 21513086 is 68031512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 768311 + ... + 768338.

It is an arithmetic number, because the mean of its divisors is an integer number (4609950).

Almost surely, 2^21513086 is an apocalyptic number.

21513086 is a deficient number, since it is larger than the sum of its proper divisors (15366514).

21513086 is a wasteful number, since it uses less digits than its factorization.

21513086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536658.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21513086 is about 4638.2201327664. The cubic root of 21513086 is about 278.1212917235.

Adding to 21513086 its reverse (68031512), we get a palindrome (89544598).

The spelling of 21513086 in words is "twenty-one million, five hundred thirteen thousand, eighty-six".