21720551046 has 16 divisors (see below), whose sum is σ = 43513632000. Its totient is φ = 7228095368.

The previous prime is 21720551029. The next prime is 21720551053. The reversal of 21720551046 is 64015502712.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21720550998 and 21720551016.

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, 3018186 + ... + 3025373.

It is an arithmetic number, because the mean of its divisors is an integer number (2719602000).

Almost surely, 2^21720551046 is an apocalyptic number.

21720551046 is an abundant number, since it is smaller than the sum of its proper divisors (21793080954).

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

21720551046 is a wasteful number, since it uses less digits than its factorization.

21720551046 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6044163.

The product of its (nonzero) digits is 16800, while the sum is 33.

The spelling of 21720551046 in words is "twenty-one billion, seven hundred twenty million, five hundred fifty-one thousand, forty-six".