20661621712 has 40 divisors (see below), whose sum is σ = 40572001440. Its totient is φ = 10192156800.

The previous prime is 20661621703. The next prime is 20661621727. The reversal of 20661621712 is 21712616602.

It is a super-2 number, since 2×20661621712² (a number of 21 digits) contains 22 as substring.

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, 434739 + ... + 479917.

It is an arithmetic number, because the mean of its divisors is an integer number (1014300036).

Almost surely, 2^20661621712 is an apocalyptic number.

It is an amenable number.

20661621712 is a deficient number, since it is larger than the sum of its proper divisors (19910379728).

20661621712 is a wasteful number, since it uses less digits than its factorization.

20661621712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45571 (or 45565 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 34.

The spelling of 20661621712 in words is "twenty billion, six hundred sixty-one million, six hundred twenty-one thousand, seven hundred twelve".