77805420 has 144 divisors (see below), whose sum is σ = 273848064. Its totient is φ = 16156800.

The previous prime is 77805391. The next prime is 77805449. The reversal of 77805420 is 2450877.

It is an interprime number because it is at equal distance from previous prime (77805391) and next prime (77805449).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 50055 + ... + 51585.

Almost surely, 2^77805420 is an apocalyptic number.

77805420 is a gapful number since it is divisible by the number (70) 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 77805420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136924032).

77805420 is an abundant number, since it is smaller than the sum of its proper divisors (196042644).

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

77805420 is a wasteful number, since it uses less digits than its factorization.

77805420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1572 (or 1559 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 33.

The square root of 77805420 is about 8820.7380643572. The cubic root of 77805420 is about 426.9102843213.

The spelling of 77805420 in words is "seventy-seven million, eight hundred five thousand, four hundred twenty".