21371534 has 4 divisors (see below), whose sum is σ = 32057304. Its totient is φ = 10685766.

The previous prime is 21371509. The next prime is 21371551. The reversal of 21371534 is 43517312.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5342882 + ... + 5342885.

It is an arithmetic number, because the mean of its divisors is an integer number (8014326).

Almost surely, 2^21371534 is an apocalyptic number.

21371534 is a deficient number, since it is larger than the sum of its proper divisors (10685770).

21371534 is a wasteful number, since it uses less digits than its factorization.

21371534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10685769.

The product of its digits is 2520, while the sum is 26.

The square root of 21371534 is about 4622.9356473998. The cubic root of 21371534 is about 277.5099539216.

Adding to 21371534 its reverse (43517312), we get a palindrome (64888846).

The spelling of 21371534 in words is "twenty-one million, three hundred seventy-one thousand, five hundred thirty-four".