12861147649 has 27 divisors (see below), whose sum is σ = 15909443337. Its totient is φ = 10364492544.

The previous prime is 12861147641. The next prime is 12861147667. The reversal of 12861147649 is 94674116821.

The square root of 12861147649 is 113407.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 566773249 + 12294374400 = 23807^2 + 110880^2 .

It is not a de Polignac number, because 12861147649 - 2³ = 12861147641 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12861147641) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 13494957 + ... + 13495909.

Almost surely, 2^12861147649 is an apocalyptic number.

12861147649 is the 113407-th square number.

12861147649 is the 56704-th centered octagonal number.

It is an amenable number.

12861147649 is a deficient number, since it is larger than the sum of its proper divisors (3048295688).

12861147649 is an frugal number, since it uses more digits than its factorization.

12861147649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1954 (or 977 counting only the distinct ones).

The product of its digits is 580608, while the sum is 49.

Multiplying 12861147649 by its sum of digits (49), we get a square (630196234801 = 793849²).

12861147649 divided by its sum of digits (49) gives a square (262472401 = 16201²).

The spelling of 12861147649 in words is "twelve billion, eight hundred sixty-one million, one hundred forty-seven thousand, six hundred forty-nine".