21551534 has 8 divisors (see below), whose sum is σ = 32526120. Its totient is φ = 10709496.

The previous prime is 21551503. The next prime is 21551539. The reversal of 21551534 is 43515512.

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 (21551539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32729 + ... + 33380.

It is an arithmetic number, because the mean of its divisors is an integer number (4065765).

Almost surely, 2^21551534 is an apocalyptic number.

21551534 is a deficient number, since it is larger than the sum of its proper divisors (10974586).

21551534 is a wasteful number, since it uses less digits than its factorization.

21551534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66274.

The product of its digits is 3000, while the sum is 26.

The square root of 21551534 is about 4642.3629758992. The cubic root of 21551534 is about 278.2868784346.

The spelling of 21551534 in words is "twenty-one million, five hundred fifty-one thousand, five hundred thirty-four".