1211431540 has 24 divisors (see below), whose sum is σ = 2775280032. Its totient is φ = 440520480.

The previous prime is 1211431531. The next prime is 1211431579. The reversal of 1211431540 is 451341121.

It is a super-3 number, since 3×1211431540³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2753034 + ... + 2753473.

It is an arithmetic number, because the mean of its divisors is an integer number (115636668).

Almost surely, 2^1211431540 is an apocalyptic number.

1211431540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211431540 is an abundant number, since it is smaller than the sum of its proper divisors (1563848492).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211431540 is a wasteful number, since it uses less digits than its factorization.

1211431540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5506527 (or 5506525 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 1211431540 is about 34805.6251200866. The cubic root of 1211431540 is about 1066.0223059231.

Adding to 1211431540 its reverse (451341121), we get a palindrome (1662772661).

The spelling of 1211431540 in words is "one billion, two hundred eleven million, four hundred thirty-one thousand, five hundred forty".