20643166442 has 4 divisors (see below), whose sum is σ = 30964749666. Its totient is φ = 10321583220.

The previous prime is 20643166421. The next prime is 20643166447. The reversal of 20643166442 is 24466134602.

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., 11060518561 + 9582647881 = 105169^2 + 97891^2 .

It is a super-2 number, since 2×20643166442² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20643166396 and 20643166405.

It is not an unprimeable number, because it can be changed into a prime (20643166447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5160791609 + ... + 5160791612.

Almost surely, 2^20643166442 is an apocalyptic number.

20643166442 is a deficient number, since it is larger than the sum of its proper divisors (10321583224).

20643166442 is a wasteful number, since it uses less digits than its factorization.

20643166442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10321583223.

The product of its (nonzero) digits is 165888, while the sum is 38.

The spelling of 20643166442 in words is "twenty billion, six hundred forty-three million, one hundred sixty-six thousand, four hundred forty-two".