1166521651 has 4 divisors (see below), whose sum is σ = 1172966704. Its totient is φ = 1160076600.

The previous prime is 1166521639. The next prime is 1166521669. The reversal of 1166521651 is 1561256611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1561256611 = 1889 ⋅826499.

It is a cyclic number.

It is not a de Polignac number, because 1166521651 - 2¹³ = 1166513459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1166527651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3222255 + ... + 3222616.

It is an arithmetic number, because the mean of its divisors is an integer number (293241676).

Almost surely, 2^1166521651 is an apocalyptic number.

1166521651 is a deficient number, since it is larger than the sum of its proper divisors (6445053).

1166521651 is an equidigital number, since it uses as much as digits as its factorization.

1166521651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6445052.

The product of its digits is 10800, while the sum is 34.

The square root of 1166521651 is about 34154.3796752335. The cubic root of 1166521651 is about 1052.6829801307.

The spelling of 1166521651 in words is "one billion, one hundred sixty-six million, five hundred twenty-one thousand, six hundred fifty-one".