1311999990 has 96 divisors (see below), whose sum is σ = 3878427744. Its totient is φ = 282240000.

The previous prime is 1311999979. The next prime is 1312000003. The reversal of 1311999990 is 999991131.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1261 + ... + 51240.

It is an arithmetic number, because the mean of its divisors is an integer number (40400289).

Almost surely, 2^1311999990 is an apocalyptic number.

1311999990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1311999990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1939213872).

1311999990 is an abundant number, since it is smaller than the sum of its proper divisors (2566427754).

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

1311999990 is a wasteful number, since it uses less digits than its factorization.

1311999990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52542 (or 52535 counting only the distinct ones).

The product of its (nonzero) digits is 177147, while the sum is 51.

The square root of 1311999990 is about 36221.5404145103. The cubic root of 1311999990 is about 1094.7407321783.

The spelling of 1311999990 in words is "one billion, three hundred eleven million, nine hundred ninety-nine thousand, nine hundred ninety".