1211215440 has 80 divisors (see below), whose sum is σ = 3846378816. Its totient is φ = 315110400.

The previous prime is 1211215409. The next prime is 1211215459. The reversal of 1211215440 is 445121121.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

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, 51706 + ... + 71385.

Almost surely, 2^1211215440 is an apocalyptic number.

1211215440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211215440 is an abundant number, since it is smaller than the sum of its proper divisors (2635163376).

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

1211215440 is a wasteful number, since it uses less digits than its factorization.

1211215440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123148 (or 123142 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 1211215440 is about 34802.5205983705. The cubic root of 1211215440 is about 1065.9589150471.

Adding to 1211215440 its reverse (445121121), we get a palindrome (1656336561).

The spelling of 1211215440 in words is "one billion, two hundred eleven million, two hundred fifteen thousand, four hundred forty".