1211566151 has 4 divisors (see below), whose sum is σ = 1239742152. Its totient is φ = 1183390152.

The previous prime is 1211566133. The next prime is 1211566219. The reversal of 1211566151 is 1516651121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1516651121 = 1847 ⋅821143.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211566151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211560151) 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, 14087936 + ... + 14088021.

It is an arithmetic number, because the mean of its divisors is an integer number (309935538).

Almost surely, 2^1211566151 is an apocalyptic number.

1211566151 is a deficient number, since it is larger than the sum of its proper divisors (28176001).

1211566151 is an equidigital number, since it uses as much as digits as its factorization.

1211566151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28176000.

The product of its digits is 1800, while the sum is 29.

The square root of 1211566151 is about 34807.5588198885. The cubic root of 1211566151 is about 1066.0617889670.

The spelling of 1211566151 in words is "one billion, two hundred eleven million, five hundred sixty-six thousand, one hundred fifty-one".