78420877 has 4 divisors (see below), whose sum is σ = 78438816. Its totient is φ = 78402940.

The previous prime is 78420857. The next prime is 78420889. The reversal of 78420877 is 77802487.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 77802487 = 7 ⋅11114641.

It is a cyclic number.

It is not a de Polignac number, because 78420877 - 2¹¹ = 78418829 is a prime.

It is a super-2 number, since 2×78420877² = 12299667898898258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78420817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2352 + ... + 12742.

It is an arithmetic number, because the mean of its divisors is an integer number (19609704).

Almost surely, 2^78420877 is an apocalyptic number.

It is an amenable number.

78420877 is a deficient number, since it is larger than the sum of its proper divisors (17939).

78420877 is a wasteful number, since it uses less digits than its factorization.

78420877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17938.

The product of its (nonzero) digits is 175616, while the sum is 43.

The square root of 78420877 is about 8855.5562784051. The cubic root of 78420877 is about 428.0329788691.

It can be divided in two parts, 78420 and 877, that added together give a palindrome (79297).

The spelling of 78420877 in words is "seventy-eight million, four hundred twenty thousand, eight hundred seventy-seven".