78930421 has 2 divisors, whose sum is σ = 78930422. Its totient is φ = 78930420.

The previous prime is 78930419. The next prime is 78930461. The reversal of 78930421 is 12403987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47458321 + 31472100 = 6889^2 + 5610^2 .

It is a cyclic number.

It is not a de Polignac number, because 78930421 - 2¹ = 78930419 is a prime.

It is a super-2 number, since 2×78930421² = 12460022718474482, which contains 22 as substring.

Together with 78930419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78930461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39465210 + 39465211.

It is an arithmetic number, because the mean of its divisors is an integer number (39465211).

Almost surely, 2^78930421 is an apocalyptic number.

It is an amenable number.

78930421 is a deficient number, since it is larger than the sum of its proper divisors (1).

78930421 is an equidigital number, since it uses as much as digits as its factorization.

78930421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 78930421 is about 8884.2794305447. The cubic root of 78930421 is about 428.9580342306.

The spelling of 78930421 in words is "seventy-eight million, nine hundred thirty thousand, four hundred twenty-one".