1620553536 has 168 divisors, whose sum is σ = 5438631744. Its totient is φ = 451676160.

The previous prime is 1620553523. The next prime is 1620553541. The reversal of 1620553536 is 6353550261.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1620553536.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 160411 + ... + 170213.

It is an arithmetic number, because the mean of its divisors is an integer number (32372808).

Almost surely, 2^1620553536 is an apocalyptic number.

1620553536 is a gapful number since it is divisible by the number (16) 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 1620553536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2719315872).

1620553536 is an abundant number, since it is smaller than the sum of its proper divisors (3818078208).

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

1620553536 is a wasteful number, since it uses less digits than its factorization.

1620553536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9869 (or 9856 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 36.

The square root of 1620553536 is about 40256.0993639473. The cubic root of 1620553536 is about 1174.5940437955.

The spelling of 1620553536 in words is "one billion, six hundred twenty million, five hundred fifty-three thousand, five hundred thirty-six".