1215244755661 has 24 divisors (see below), whose sum is σ = 1322555314752. Its totient is φ = 1114395638400.

The previous prime is 1215244755607. The next prime is 1215244755667. The reversal of 1215244755661 is 1665574425121.

It is a happy number.

It is not a de Polignac number, because 1215244755661 - 2⁷ = 1215244755533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215244755667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2108101 + ... + 2621941.

It is an arithmetic number, because the mean of its divisors is an integer number (55106471448).

Almost surely, 2^{1215244755661} is an apocalyptic number.

It is an amenable number.

1215244755661 is a deficient number, since it is larger than the sum of its proper divisors (107310559091).

1215244755661 is a wasteful number, since it uses less digits than its factorization.

1215244755661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514033 (or 514002 counting only the distinct ones).

The product of its digits is 2016000, while the sum is 49.

The spelling of 1215244755661 in words is "one trillion, two hundred fifteen billion, two hundred forty-four million, seven hundred fifty-five thousand, six hundred sixty-one".