20660408642 has 4 divisors (see below), whose sum is σ = 30990612966. Its totient is φ = 10330204320.

The previous prime is 20660408623. The next prime is 20660408677. The reversal of 20660408642 is 24680406602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19301822761 + 1358585881 = 138931^2 + 36859^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20660408596 and 20660408605.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5165102159 + ... + 5165102162.

Almost surely, 2^20660408642 is an apocalyptic number.

20660408642 is a deficient number, since it is larger than the sum of its proper divisors (10330204324).

20660408642 is a wasteful number, since it uses less digits than its factorization.

20660408642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10330204323.

The product of its (nonzero) digits is 110592, while the sum is 38.

The spelling of 20660408642 in words is "twenty billion, six hundred sixty million, four hundred eight thousand, six hundred forty-two".