1641561600 has 480 divisors, whose sum is σ = 6429874176. Its totient is φ = 361267200.

The previous prime is 1641561587. The next prime is 1641561613. The reversal of 1641561600 is 61651461.

It is an interprime number because it is at equal distance from previous prime (1641561587) and next prime (1641561613).

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-3 number, since 3×1641561600³ (a number of 29 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8332702 + ... + 8332898.

Almost surely, 2^1641561600 is an apocalyptic number.

1641561600 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 1641561600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3214937088).

1641561600 is an abundant number, since it is smaller than the sum of its proper divisors (4788312576).

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

1641561600 is a wasteful number, since it uses less digits than its factorization.

1641561600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1641561600 is about 40516.1893568485. The cubic root of 1641561600 is about 1179.6478888122.

The spelling of 1641561600 in words is "one billion, six hundred forty-one million, five hundred sixty-one thousand, six hundred".