21558141 has 48 divisors (see below), whose sum is σ = 36479040. Its totient is φ = 12130560.

The previous prime is 21558137. The next prime is 21558143. The reversal of 21558141 is 14185512.

It is not a de Polignac number, because 21558141 - 2² = 21558137 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21558143) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 137235 + ... + 137391.

It is an arithmetic number, because the mean of its divisors is an integer number (759980).

Almost surely, 2^21558141 is an apocalyptic number.

It is an amenable number.

21558141 is a deficient number, since it is larger than the sum of its proper divisors (14920899).

21558141 is a wasteful number, since it uses less digits than its factorization.

21558141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266 (or 263 counting only the distinct ones).

The product of its digits is 1600, while the sum is 27.

The square root of 21558141 is about 4643.0745201860. The cubic root of 21558141 is about 278.3153134337.

It can be divided in two parts, 2155 and 8141, that added together give a triangular number (10296 = T₁₄₃).

The spelling of 21558141 in words is "twenty-one million, five hundred fifty-eight thousand, one hundred forty-one".