1321761540 has 48 divisors (see below), whose sum is σ = 4037382720. Its totient is φ = 320426880.

The previous prime is 1321761523. The next prime is 1321761547. The reversal of 1321761540 is 451671231.

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

It is a junction number, because it is equal to n+sod(n) for n = 1321761498 and 1321761507.

It is not an unprimeable number, because it can be changed into a prime (1321761547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1000675 + ... + 1001994.

It is an arithmetic number, because the mean of its divisors is an integer number (84112140).

Almost surely, 2^1321761540 is an apocalyptic number.

1321761540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321761540 is an abundant number, since it is smaller than the sum of its proper divisors (2715621180).

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

1321761540 is a wasteful number, since it uses less digits than its factorization.

1321761540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2002692 (or 2002690 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 1321761540 is about 36356.0385630778. The cubic root of 1321761540 is about 1097.4490585405.

The spelling of 1321761540 in words is "one billion, three hundred twenty-one million, seven hundred sixty-one thousand, five hundred forty".