21513037 has 8 divisors (see below), whose sum is σ = 26477696. Its totient is φ = 17021232.

The previous prime is 21513031. The next prime is 21513049. The reversal of 21513037 is 73031512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21513037 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21512999 and 21513017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118113 + ... + 118294.

It is an arithmetic number, because the mean of its divisors is an integer number (3309712).

Almost surely, 2^21513037 is an apocalyptic number.

It is an amenable number.

21513037 is a deficient number, since it is larger than the sum of its proper divisors (4964659).

21513037 is a wasteful number, since it uses less digits than its factorization.

21513037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236427.

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 21513037 is about 4638.2148505648. The cubic root of 21513037 is about 278.1210805659.

Adding to 21513037 its reverse (73031512), we get a palindrome (94544549).

The spelling of 21513037 in words is "twenty-one million, five hundred thirteen thousand, thirty-seven".