21006631658 has 8 divisors (see below), whose sum is σ = 31510926720. Its totient is φ = 10502989420.

The previous prime is 21006631651. The next prime is 21006631663. The reversal of 21006631658 is 85613660012.

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

It is a super-2 number, since 2×21006631658² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21006631651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72728 + ... + 217491.

It is an arithmetic number, because the mean of its divisors is an integer number (3938865840).

Almost surely, 2^21006631658 is an apocalyptic number.

21006631658 is a deficient number, since it is larger than the sum of its proper divisors (10504295062).

21006631658 is a wasteful number, since it uses less digits than its factorization.

21006631658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326412.

The product of its (nonzero) digits is 51840, while the sum is 38.

The spelling of 21006631658 in words is "twenty-one billion, six million, six hundred thirty-one thousand, six hundred fifty-eight".