21331534 has 32 divisors (see below), whose sum is σ = 39407616. Its totient is φ = 8458560.

The previous prime is 21331523. The next prime is 21331537. The reversal of 21331534 is 43513312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331537) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8914 + ... + 11050.

It is an arithmetic number, because the mean of its divisors is an integer number (1231488).

Almost surely, 2^21331534 is an apocalyptic number.

21331534 is a deficient number, since it is larger than the sum of its proper divisors (18076082).

21331534 is a wasteful number, since it uses less digits than its factorization.

21331534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200.

The product of its digits is 1080, while the sum is 22.

The square root of 21331534 is about 4618.6073658626. The cubic root of 21331534 is about 277.3367120957.

Adding to 21331534 its reverse (43513312), we get a palindrome (64844846).

The spelling of 21331534 in words is "twenty-one million, three hundred thirty-one thousand, five hundred thirty-four".