1211521451 has 16 divisors (see below), whose sum is σ = 1425229824. Its totient is φ = 1008098784.

The previous prime is 1211521411. The next prime is 1211521457. The reversal of 1211521451 is 1541251121.

It is a happy number.

It is not a de Polignac number, because 1211521451 - 2³⁰ = 137779627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211521457) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114866 + ... + 124968.

It is an arithmetic number, because the mean of its divisors is an integer number (89076864).

Almost surely, 2^1211521451 is an apocalyptic number.

1211521451 is a deficient number, since it is larger than the sum of its proper divisors (213708373).

1211521451 is a wasteful number, since it uses less digits than its factorization.

1211521451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10610.

The product of its digits is 400, while the sum is 23.

The square root of 1211521451 is about 34806.9167120560. The cubic root of 1211521451 is about 1066.0486782376.

Adding to 1211521451 its reverse (1541251121), we get a palindrome (2752772572).

The spelling of 1211521451 in words is "one billion, two hundred eleven million, five hundred twenty-one thousand, four hundred fifty-one".