1171564921 has 2 divisors, whose sum is σ = 1171564922. Its totient is φ = 1171564920.

The previous prime is 1171564897. The next prime is 1171564937. The reversal of 1171564921 is 1294651711.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1153621225 + 17943696 = 33965^2 + 4236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1171564921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1171564621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 585782460 + 585782461.

It is an arithmetic number, because the mean of its divisors is an integer number (585782461).

Almost surely, 2^1171564921 is an apocalyptic number.

It is an amenable number.

1171564921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1171564921 is an equidigital number, since it uses as much as digits as its factorization.

1171564921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 37.

The square root of 1171564921 is about 34228.1305507619. The cubic root of 1171564921 is about 1054.1978347106.

It can be divided in two parts, 11715 and 64921, that added together give a triangular number (76636 = T₃₉₁).

The spelling of 1171564921 in words is "one billion, one hundred seventy-one million, five hundred sixty-four thousand, nine hundred twenty-one".