1381161720 has 64 divisors (see below), whose sum is σ = 4239861120. Its totient is φ = 359743104.

The previous prime is 1381161697. The next prime is 1381161731. The reversal of 1381161720 is 271611831.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 128674 + ... + 138993.

It is an arithmetic number, because the mean of its divisors is an integer number (66247830).

Almost surely, 2^1381161720 is an apocalyptic number.

1381161720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1381161720 is an abundant number, since it is smaller than the sum of its proper divisors (2858699400).

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

1381161720 is a wasteful number, since it uses less digits than its factorization.

1381161720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267724 (or 267720 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 1381161720 is about 37163.9841782336. The cubic root of 1381161720 is about 1113.6486057382.

The spelling of 1381161720 in words is "one billion, three hundred eighty-one million, one hundred sixty-one thousand, seven hundred twenty".