1020420641565 has 64 divisors (see below), whose sum is σ = 1953882766080. Its totient is φ = 502294867200.

The previous prime is 1020420641561. The next prime is 1020420641599. The reversal of 1020420641565 is 5651460240201.

1020420641565 is a `hidden beast` number, since 1 + 0 + 2 + 0 + 4 + 2 + 0 + 641 + 5 + 6 + 5 = 666.

It is not a de Polignac number, because 1020420641565 - 2² = 1020420641561 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020420641561) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14994115 + ... + 15062015.

It is an arithmetic number, because the mean of its divisors is an integer number (30529418220).

Almost surely, 2^{1020420641565} is an apocalyptic number.

1020420641565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1020420641565 is a deficient number, since it is larger than the sum of its proper divisors (933462124515).

1020420641565 is a wasteful number, since it uses less digits than its factorization.

1020420641565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76491 (or 76485 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

Adding to 1020420641565 its reverse (5651460240201), we get a palindrome (6671880881766).

The spelling of 1020420641565 in words is "one trillion, twenty billion, four hundred twenty million, six hundred forty-one thousand, five hundred sixty-five".