21315534 has 32 divisors (see below), whose sum is σ = 43946496. Its totient is φ = 6888960.

The previous prime is 21315521. The next prime is 21315557. The reversal of 21315534 is 43551312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36654 + ... + 37230.

It is an arithmetic number, because the mean of its divisors is an integer number (1373328).

Almost surely, 2^21315534 is an apocalyptic number.

21315534 is an abundant number, since it is smaller than the sum of its proper divisors (22630962).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21315534 is a wasteful number, since it uses less digits than its factorization.

21315534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760.

The product of its digits is 1800, while the sum is 24.

The square root of 21315534 is about 4616.8749170841. The cubic root of 21315534 is about 277.2673547256.

Adding to 21315534 its reverse (43551312), we get a palindrome (64866846).

The spelling of 21315534 in words is "twenty-one million, three hundred fifteen thousand, five hundred thirty-four".