78637213 has 4 divisors (see below), whose sum is σ = 80120988. Its totient is φ = 77153440.

The previous prime is 78637201. The next prime is 78637259. The reversal of 78637213 is 31273687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31273687 = 29 ⋅1078403.

It can be written as a sum of positive squares in 2 ways, for example, as 62299449 + 16337764 = 7893^2 + 4042^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78637213 is a prime.

It is a super-2 number, since 2×78637213² = 12367622536814738, 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 (78631213) 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, 741808 + ... + 741913.

It is an arithmetic number, because the mean of its divisors is an integer number (20030247).

Almost surely, 2^78637213 is an apocalyptic number.

It is an amenable number.

78637213 is a deficient number, since it is larger than the sum of its proper divisors (1483775).

78637213 is a wasteful number, since it uses less digits than its factorization.

78637213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1483774.

The product of its digits is 42336, while the sum is 37.

The square root of 78637213 is about 8867.7625701188. The cubic root of 78637213 is about 428.4262156655.

The spelling of 78637213 in words is "seventy-eight million, six hundred thirty-seven thousand, two hundred thirteen".