78209520 has 160 divisors (see below), whose sum is σ = 265965120. Its totient is φ = 18923520.

The previous prime is 78209507. The next prime is 78209533. The reversal of 78209520 is 2590287.

It is an interprime number because it is at equal distance from previous prime (78209507) and next prime (78209533).

It is a super-2 number, since 2×78209520² = 12233458037260800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117990 + ... + 118650.

It is an arithmetic number, because the mean of its divisors is an integer number (1662282).

Almost surely, 2^78209520 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 78209520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132982560).

78209520 is an abundant number, since it is smaller than the sum of its proper divisors (187755600).

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

78209520 is a wasteful number, since it uses less digits than its factorization.

78209520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723 (or 717 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 78209520 is about 8843.6146456073. The cubic root of 78209520 is about 427.6480934202.

The spelling of 78209520 in words is "seventy-eight million, two hundred nine thousand, five hundred twenty".