1212157440 has 640 divisors, whose sum is σ = 4949683200. Its totient is φ = 278691840.

The previous prime is 1212157433. The next prime is 1212157451. The reversal of 1212157440 is 447512121.

1212157440 is a `hidden beast` number, since 1 + 2 + 1 + 215 + 7 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17072605 + ... + 17072675.

It is an arithmetic number, because the mean of its divisors is an integer number (7733880).

Almost surely, 2^1212157440 is an apocalyptic number.

1212157440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1212157440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2474841600).

1212157440 is an abundant number, since it is smaller than the sum of its proper divisors (3737525760).

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

1212157440 is a wasteful number, since it uses less digits than its factorization.

1212157440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 1212157440 is about 34816.0514705502. The cubic root of 1212157440 is about 1066.2351865955.

Adding to 1212157440 its reverse (447512121), we get a palindrome (1659669561).

The spelling of 1212157440 in words is "one billion, two hundred twelve million, one hundred fifty-seven thousand, four hundred forty".