1620695640 has 64 divisors (see below), whose sum is σ = 4877832960. Its totient is φ = 430785920.

The previous prime is 1620695633. The next prime is 1620695651. The reversal of 1620695640 is 465960261.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

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, 15607 + ... + 59033.

It is an arithmetic number, because the mean of its divisors is an integer number (76216140).

Almost surely, 2^1620695640 is an apocalyptic number.

1620695640 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 1620695640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2438916480).

1620695640 is an abundant number, since it is smaller than the sum of its proper divisors (3257137320).

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

1620695640 is a wasteful number, since it uses less digits than its factorization.

1620695640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43752 (or 43748 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 1620695640 is about 40257.8643248745. The cubic root of 1620695640 is about 1174.6283756106.

The spelling of 1620695640 in words is "one billion, six hundred twenty million, six hundred ninety-five thousand, six hundred forty".