20721375456 has 48 divisors (see below), whose sum is σ = 54417339648. Its totient is φ = 6904112000.

The previous prime is 20721375443. The next prime is 20721375469. The reversal of 20721375456 is 65457312702.

It is an interprime number because it is at equal distance from previous prime (20721375443) and next prime (20721375469).

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179791 + ... + 271601.

It is an arithmetic number, because the mean of its divisors is an integer number (1133694576).

Almost surely, 2^20721375456 is an apocalyptic number.

It is an amenable number.

20721375456 is an abundant number, since it is smaller than the sum of its proper divisors (33695964192).

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

20721375456 is a wasteful number, since it uses less digits than its factorization.

20721375456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94175 (or 94167 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 42.

The spelling of 20721375456 in words is "twenty billion, seven hundred twenty-one million, three hundred seventy-five thousand, four hundred fifty-six".