21218058 has 16 divisors (see below), whose sum is σ = 47151360. Its totient is φ = 7072668.

The previous prime is 21218011. The next prime is 21218059. The reversal of 21218058 is 85081212.

It is a super-3 number, since 3×21218058³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21218059) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196410 + ... + 196517.

It is an arithmetic number, because the mean of its divisors is an integer number (2946960).

Almost surely, 2^21218058 is an apocalyptic number.

21218058 is an abundant number, since it is smaller than the sum of its proper divisors (25933302).

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

21218058 is a wasteful number, since it uses less digits than its factorization.

21218058 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392938 (or 392932 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21218058 is about 4606.3063293706. The cubic root of 21218058 is about 276.8440606824.

The spelling of 21218058 in words is "twenty-one million, two hundred eighteen thousand, fifty-eight".