1211388738 has 64 divisors (see below), whose sum is σ = 2937815040. Its totient is φ = 325285632.

The previous prime is 1211388727. The next prime is 1211388749. The reversal of 1211388738 is 8378831121.

It is an interprime number because it is at equal distance from previous prime (1211388727) and next prime (1211388749).

It is a super-3 number, since 3×1211388738³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211388738.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 95370 + ... + 107322.

It is an arithmetic number, because the mean of its divisors is an integer number (45903360).

Almost surely, 2^1211388738 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211388738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1468907520).

1211388738 is an abundant number, since it is smaller than the sum of its proper divisors (1726426302).

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

1211388738 is a wasteful number, since it uses less digits than its factorization.

1211388738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12111.

The product of its digits is 64512, while the sum is 42.

The square root of 1211388738 is about 34805.0102427797. The cubic root of 1211388738 is about 1066.0097509630.

The spelling of 1211388738 in words is "one billion, two hundred eleven million, three hundred eighty-eight thousand, seven hundred thirty-eight".