20405220646 has 4 divisors (see below), whose sum is σ = 30607830972. Its totient is φ = 10202610322.

The previous prime is 20405220571. The next prime is 20405220653. The reversal of 20405220646 is 64602250402.

20405220646 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-2 number, since 2×20405220646² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 5101305160 + ... + 5101305163.

It is an arithmetic number, because the mean of its divisors is an integer number (7651957743).

Almost surely, 2^20405220646 is an apocalyptic number.

20405220646 is a deficient number, since it is larger than the sum of its proper divisors (10202610326).

20405220646 is a wasteful number, since it uses less digits than its factorization.

20405220646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10202610325.

The product of its (nonzero) digits is 23040, while the sum is 31.

The spelling of 20405220646 in words is "twenty billion, four hundred five million, two hundred twenty thousand, six hundred forty-six".