78213571 has 4 divisors (see below), whose sum is σ = 78247672. Its totient is φ = 78179472.

The previous prime is 78213563. The next prime is 78213607. The reversal of 78213571 is 17531287.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78213571 - 2³ = 78213563 is a prime.

It is a super-2 number, since 2×78213571² = 12234725377144082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78213511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13341 + ... + 18286.

It is an arithmetic number, because the mean of its divisors is an integer number (19561918).

Almost surely, 2^78213571 is an apocalyptic number.

78213571 is a deficient number, since it is larger than the sum of its proper divisors (34101).

78213571 is a wasteful number, since it uses less digits than its factorization.

78213571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34100.

The product of its digits is 11760, while the sum is 34.

The square root of 78213571 is about 8843.8436779491. The cubic root of 78213571 is about 427.6554768885.

The spelling of 78213571 in words is "seventy-eight million, two hundred thirteen thousand, five hundred seventy-one".