1211987969 has 8 divisors (see below), whose sum is σ = 1217508000. Its totient is φ = 1206477216.

The previous prime is 1211987957. The next prime is 1211987983. The reversal of 1211987969 is 9697891121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211987969 is a prime.

It is a super-2 number, since 2×1211987969² = 2937829674001489922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211987969.

It is not an unprimeable number, because it can be changed into a prime (1211987999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 422789 + ... + 425645.

It is an arithmetic number, because the mean of its divisors is an integer number (152188500).

Almost surely, 2^1211987969 is an apocalyptic number.

It is an amenable number.

1211987969 is a deficient number, since it is larger than the sum of its proper divisors (5520031).

1211987969 is a wasteful number, since it uses less digits than its factorization.

1211987969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4639.

The product of its digits is 489888, while the sum is 53.

The square root of 1211987969 is about 34813.6175799069. The cubic root of 1211987969 is about 1066.1854943804.

The spelling of 1211987969 in words is "one billion, two hundred eleven million, nine hundred eighty-seven thousand, nine hundred sixty-nine".