20976311666 has 4 divisors (see below), whose sum is σ = 31464467502. Its totient is φ = 10488155832.

The previous prime is 20976311659. The next prime is 20976311677. The reversal of 20976311666 is 66611367902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66611367902 = 2 ⋅33305683951.

It can be written as a sum of positive squares in only one way, i.e., 20485910641 + 490401025 = 143129^2 + 22145^2 .

It is a super-2 number, since 2×20976311666² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20976311666.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5244077915 + ... + 5244077918.

Almost surely, 2^20976311666 is an apocalyptic number.

20976311666 is a deficient number, since it is larger than the sum of its proper divisors (10488155836).

20976311666 is a wasteful number, since it uses less digits than its factorization.

20976311666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10488155835.

The product of its (nonzero) digits is 489888, while the sum is 47.

The spelling of 20976311666 in words is "twenty billion, nine hundred seventy-six million, three hundred eleven thousand, six hundred sixty-six".