1205561530251 has 192 divisors, whose sum is σ = 2032499589120. Its totient is φ = 687227224320.

The previous prime is 1205561530211. The next prime is 1205561530253. The reversal of 1205561530251 is 1520351655021.

1205561530251 is a `hidden beast` number, since 1 + 2 + 0 + 5 + 5 + 615 + 30 + 2 + 5 + 1 = 666.

It is not a de Polignac number, because 1205561530251 - 2¹³ = 1205561522059 is a prime.

It is a super-2 number, since 2×1205561530251² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1205561530253) by changing a digit.

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 in 191 ways as a sum of consecutive naturals, for example, 1396942246 + ... + 1396943108.

It is an arithmetic number, because the mean of its divisors is an integer number (10585935360).

Almost surely, 2^{1205561530251} is an apocalyptic number.

1205561530251 is a deficient number, since it is larger than the sum of its proper divisors (826938058869).

1205561530251 is a wasteful number, since it uses less digits than its factorization.

1205561530251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035 (or 1006 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

The spelling of 1205561530251 in words is "one trillion, two hundred five billion, five hundred sixty-one million, five hundred thirty thousand, two hundred fifty-one".