1656172980 has 720 divisors, whose sum is σ = 7007793408. Its totient is φ = 319334400.

The previous prime is 1656172979. The next prime is 1656173009. The reversal of 1656172980 is 892716561.

1656172980 is a `hidden beast` number, since 1 + 6 + 5 + 617 + 29 + 8 + 0 = 666.

1656172980 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 23326345 + ... + 23326415.

Almost surely, 2^1656172980 is an apocalyptic number.

1656172980 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 1656172980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3503896704).

1656172980 is an abundant number, since it is smaller than the sum of its proper divisors (5351620428).

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

1656172980 is a wasteful number, since it uses less digits than its factorization.

1656172980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 1656172980 is about 40696.1052190501. The cubic root of 1656172980 is about 1183.1375325487.

The spelling of 1656172980 in words is "one billion, six hundred fifty-six million, one hundred seventy-two thousand, nine hundred eighty".