1211542440 has 64 divisors (see below), whose sum is σ = 3639677760. Its totient is φ = 322629120.

The previous prime is 1211542439. The next prime is 1211542463. The reversal of 1211542440 is 442451121.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1211542440.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84687 + ... + 97953.

It is an arithmetic number, because the mean of its divisors is an integer number (56869965).

Almost surely, 2^1211542440 is an apocalyptic number.

1211542440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211542440 is an abundant number, since it is smaller than the sum of its proper divisors (2428135320).

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

1211542440 is a wasteful number, since it uses less digits than its factorization.

1211542440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14042 (or 14038 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 1211542440 is about 34807.2182169159. The cubic root of 1211542440 is about 1066.0548344545.

Adding to 1211542440 its reverse (442451121), we get a palindrome (1653993561).

The spelling of 1211542440 in words is "one billion, two hundred eleven million, five hundred forty-two thousand, four hundred forty".