20721855546142 has 16 divisors (see below), whose sum is σ = 31102626416400. Its totient is φ = 10354315403520.

The previous prime is 20721855546107. The next prime is 20721855546149. The reversal of 20721855546142 is 24164555812702.

It is a self number, because there is not a number n which added to its sum of digits gives 20721855546142.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20721855546149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20405284 + ... + 21396712.

It is an arithmetic number, because the mean of its divisors is an integer number (1943914151025).

Almost surely, 2^{20721855546142} is an apocalyptic number.

20721855546142 is a deficient number, since it is larger than the sum of its proper divisors (10380770870258).

20721855546142 is a wasteful number, since it uses less digits than its factorization.

20721855546142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998091.

The product of its (nonzero) digits is 5376000, while the sum is 52.

The spelling of 20721855546142 in words is "twenty trillion, seven hundred twenty-one billion, eight hundred fifty-five million, five hundred forty-six thousand, one hundred forty-two".