1264055661 has 18 divisors (see below), whose sum is σ = 2006936750. Its totient is φ = 766093680.

The previous prime is 1264055657. The next prime is 1264055687. The reversal of 1264055661 is 1665504621.

1264055661 is a `hidden beast` number, since 1 + 2 + 6 + 40 + 556 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1184667561 + 79388100 = 34419^2 + 8910^2 .

It is not a de Polignac number, because 1264055661 - 2² = 1264055657 is a prime.

It is a super-2 number, since 2×1264055661² = 3195673428212293842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1264055641) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 579286 + ... + 581463.

Almost surely, 2^1264055661 is an apocalyptic number.

1264055661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1264055661 is a deficient number, since it is larger than the sum of its proper divisors (742881089).

1264055661 is a wasteful number, since it uses less digits than its factorization.

1264055661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160777 (or 1160763 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 1264055661 is about 35553.5604546155. The cubic root of 1264055661 is about 1081.2399057006.

The spelling of 1264055661 in words is "one billion, two hundred sixty-four million, fifty-five thousand, six hundred sixty-one".