20445434646 has 128 divisors (see below), whose sum is σ = 51078988800. Its totient is φ = 5312217600.

The previous prime is 20445434629. The next prime is 20445434677. The reversal of 20445434646 is 64643454402.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 20445434598 and 20445434607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12627625 + ... + 12629243.

It is an arithmetic number, because the mean of its divisors is an integer number (399054600).

Almost surely, 2^20445434646 is an apocalyptic number.

20445434646 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 20445434646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25539494400).

20445434646 is an abundant number, since it is smaller than the sum of its proper divisors (30633554154).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20445434646 is a wasteful number, since it uses less digits than its factorization.

20445434646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1974.

The product of its (nonzero) digits is 1105920, while the sum is 42.

The spelling of 20445434646 in words is "twenty billion, four hundred forty-five million, four hundred thirty-four thousand, six hundred forty-six".