861011400649 has 9 divisors (see below), whose sum is σ = 863179792423. Its totient is φ = 858848449432.

The previous prime is 861011400643. The next prime is 861011400679. The reversal of 861011400649 is 946004110168.

The square root of 861011400649 is 927907.

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

861011400649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 700162277049 + 160849123600 = 836757^2 + 401060^2 .

It is not a de Polignac number, because 861011400649 - 2⁵ = 861011400617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861011400643) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 472303752 + ... + 472305574.

Almost surely, 2^861011400649 is an apocalyptic number.

861011400649 is the 927907-th square number.

861011400649 is the 463954-th centered octagonal number.

It is an amenable number.

861011400649 is a deficient number, since it is larger than the sum of its proper divisors (2168391774).

861011400649 is an frugal number, since it uses more digits than its factorization.

861011400649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4664 (or 2332 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The spelling of 861011400649 in words is "eight hundred sixty-one billion, eleven million, four hundred thousand, six hundred forty-nine".