1621755340 has 12 divisors (see below), whose sum is σ = 3405686256. Its totient is φ = 648702128.

The previous prime is 1621755337. The next prime is 1621755349. The reversal of 1621755340 is 435571261.

It is a junction number, because it is equal to n+sod(n) for n = 1621755296 and 1621755305.

It is not an unprimeable number, because it can be changed into a prime (1621755349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40543864 + ... + 40543903.

It is an arithmetic number, because the mean of its divisors is an integer number (283807188).

Almost surely, 2^1621755340 is an apocalyptic number.

1621755340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621755340 is an abundant number, since it is smaller than the sum of its proper divisors (1783930916).

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

1621755340 is a wasteful number, since it uses less digits than its factorization.

1621755340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81087776 (or 81087774 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 1621755340 is about 40271.0235777538. The cubic root of 1621755340 is about 1174.8843320574.

The spelling of 1621755340 in words is "one billion, six hundred twenty-one million, seven hundred fifty-five thousand, three hundred forty".