65815820 has 72 divisors (see below), whose sum is σ = 162025920. Its totient is φ = 22391040.

The previous prime is 65815801. The next prime is 65815831. The reversal of 65815820 is 2851856.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

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, 234080 + ... + 234360.

It is an arithmetic number, because the mean of its divisors is an integer number (2250360).

Almost surely, 2^65815820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65815820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81012960).

65815820 is an abundant number, since it is smaller than the sum of its proper divisors (96210100).

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

65815820 is a wasteful number, since it uses less digits than its factorization.

65815820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 534 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 65815820 is about 8112.6949899525. The cubic root of 65815820 is about 403.7477348772.

The spelling of 65815820 in words is "sixty-five million, eight hundred fifteen thousand, eight hundred twenty".