21121658 has 8 divisors (see below), whose sum is σ = 32038740. Its totient is φ = 10442080.

The previous prime is 21121651. The next prime is 21121663. The reversal of 21121658 is 85612112.

It can be written as a sum of positive squares in 2 ways, for example, as 20584369 + 537289 = 4537^2 + 733^2 .

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

It is a super-3 number, since 3×21121658³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21121651) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 59153 + ... + 59508.

Almost surely, 2^21121658 is an apocalyptic number.

21121658 is a deficient number, since it is larger than the sum of its proper divisors (10917082).

21121658 is a wasteful number, since it uses less digits than its factorization.

21121658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118752.

The product of its digits is 960, while the sum is 26.

The square root of 21121658 is about 4595.8305016613. The cubic root of 21121658 is about 276.4241622698.

The spelling of 21121658 in words is "twenty-one million, one hundred twenty-one thousand, six hundred fifty-eight".