21013554 has 8 divisors (see below), whose sum is σ = 42027120. Its totient is φ = 7004516.

The previous prime is 21013549. The next prime is 21013583. The reversal of 21013554 is 45531012.

It is a sphenic number, since it is the product of 3 distinct primes.

21013554 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21013554.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751124 + ... + 1751135.

It is an arithmetic number, because the mean of its divisors is an integer number (5253390).

Almost surely, 2^21013554 is an apocalyptic number.

21013554 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21013554 is a wasteful number, since it uses less digits than its factorization.

21013554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502264.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21013554 is about 4584.0543190499. The cubic root of 21013554 is about 275.9517611556.

Adding to 21013554 its reverse (45531012), we get a palindrome (66544566).

The spelling of 21013554 in words is "twenty-one million, thirteen thousand, five hundred fifty-four".