1616721940 has 24 divisors (see below), whose sum is σ = 3396447432. Its totient is φ = 646435200.

The previous prime is 1616721937. The next prime is 1616721941. The reversal of 1616721940 is 491276161.

It can be written as a sum of positive squares in 4 ways, for example, as 885776644 + 730945296 = 29762^2 + 27036^2 .

It is a super-2 number, since 2×1616721940² = 5227579662554727200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1616721940.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1616721941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41490 + ... + 70390.

It is an arithmetic number, because the mean of its divisors is an integer number (141518643).

Almost surely, 2^1616721940 is an apocalyptic number.

1616721940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1616721940 is an abundant number, since it is smaller than the sum of its proper divisors (1779725492).

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

1616721940 is a wasteful number, since it uses less digits than its factorization.

1616721940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31707 (or 31705 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 1616721940 is about 40208.4809461885. The cubic root of 1616721940 is about 1173.6675863808.

The spelling of 1616721940 in words is "one billion, six hundred sixteen million, seven hundred twenty-one thousand, nine hundred forty".