21667824026642 has 8 divisors (see below), whose sum is σ = 32501755920396. Its totient is φ = 10833905386512.

The previous prime is 21667824026621. The next prime is 21667824026647. The reversal of 21667824026642 is 24662042876612.

It is a Cunningham number, because it is equal to 4654871²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 21667824026641 + 1 = 4654871^2 + 1^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21667824026647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4018988 + ... + 7712840.

Almost surely, 2^{21667824026642} is an apocalyptic number.

21667824026642 is a deficient number, since it is larger than the sum of its proper divisors (10833931893754).

21667824026642 is a wasteful number, since it uses less digits than its factorization.

21667824026642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6626812.

The product of its (nonzero) digits is 18579456, while the sum is 56.

The spelling of 21667824026642 in words is "twenty-one trillion, six hundred sixty-seven billion, eight hundred twenty-four million, twenty-six thousand, six hundred forty-two".