15621980 has 48 divisors (see below), whose sum is σ = 37902816. Its totient is φ = 5345280.

The previous prime is 15621979. The next prime is 15622003. The reversal of 15621980 is 8912651.

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, 1652 + ... + 5828.

It is an arithmetic number, because the mean of its divisors is an integer number (789642).

Almost surely, 2^15621980 is an apocalyptic number.

15621980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15621980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18951408).

15621980 is an abundant number, since it is smaller than the sum of its proper divisors (22280836).

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

15621980 is a wasteful number, since it uses less digits than its factorization.

15621980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214 (or 4212 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 15621980 is about 3952.4650536090. The cubic root of 15621980 is about 249.9838922955.

The spelling of 15621980 in words is "fifteen million, six hundred twenty-one thousand, nine hundred eighty".