21020556610672 has 20 divisors (see below), whose sum is σ = 42041113222336. Its totient is φ = 10171237069440.

The previous prime is 21020556610667. The next prime is 21020556610709. The reversal of 21020556610672 is 27601665502012.

21020556610672 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21190076733 + ... + 21190077724.

Almost surely, 2^{21020556610672} is an apocalyptic number.

It is an amenable number.

21020556610672 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21020556610672 is a wasteful number, since it uses less digits than its factorization.

21020556610672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42380154496 (or 42380154490 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 43.

The spelling of 21020556610672 in words is "twenty-one trillion, twenty billion, five hundred fifty-six million, six hundred ten thousand, six hundred seventy-two".