21521154 has 8 divisors (see below), whose sum is σ = 43042320. Its totient is φ = 7173716.

The previous prime is 21521141. The next prime is 21521183. The reversal of 21521154 is 45112512.

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

21521154 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21521154.

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, 1793424 + ... + 1793435.

It is an arithmetic number, because the mean of its divisors is an integer number (5380290).

Almost surely, 2^21521154 is an apocalyptic number.

21521154 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.

21521154 is a wasteful number, since it uses less digits than its factorization.

21521154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3586864.

The product of its digits is 400, while the sum is 21.

The square root of 21521154 is about 4639.0897814119. The cubic root of 21521154 is about 278.1560550939.

Adding to 21521154 its reverse (45112512), we get a palindrome (66633666).

The spelling of 21521154 in words is "twenty-one million, five hundred twenty-one thousand, one hundred fifty-four".