21315063 has 32 divisors (see below), whose sum is σ = 36122112. Its totient is φ = 10857600.

The previous prime is 21315061. The next prime is 21315067. The reversal of 21315063 is 36051312.

It is not a de Polignac number, because 21315063 - 2¹ = 21315061 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315061) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11373 + ... + 13113.

It is an arithmetic number, because the mean of its divisors is an integer number (1128816).

Almost surely, 2^21315063 is an apocalyptic number.

21315063 is a deficient number, since it is larger than the sum of its proper divisors (14807049).

21315063 is a wasteful number, since it uses less digits than its factorization.

21315063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1815.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21315063 is about 4616.8239082729. The cubic root of 21315063 is about 277.2653124922.

Adding to 21315063 its reverse (36051312), we get a palindrome (57366375).

The spelling of 21315063 in words is "twenty-one million, three hundred fifteen thousand, sixty-three".