1205013661621 has 16 divisors (see below), whose sum is σ = 1520455362048. Its totient is φ = 927658767600.

The previous prime is 1205013661531. The next prime is 1205013661681. The reversal of 1205013661621 is 1261663105021.

It is a cyclic number.

It is not a de Polignac number, because 1205013661621 - 2¹¹ = 1205013659573 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205013661681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94267875 + ... + 94280656.

It is an arithmetic number, because the mean of its divisors is an integer number (95028460128).

Almost surely, 2^{1205013661621} is an apocalyptic number.

1205013661621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1205013661621 is a deficient number, since it is larger than the sum of its proper divisors (315441700427).

1205013661621 is a wasteful number, since it uses less digits than its factorization.

1205013661621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188548632.

The product of its (nonzero) digits is 12960, while the sum is 34.

Adding to 1205013661621 its reverse (1261663105021), we get a palindrome (2466676766642).

The spelling of 1205013661621 in words is "one trillion, two hundred five billion, thirteen million, six hundred sixty-one thousand, six hundred twenty-one".