78293421 has 6 divisors (see below), whose sum is σ = 113090510. Its totient is φ = 52195608.

The previous prime is 78293419. The next prime is 78293447. The reversal of 78293421 is 12439287.

It can be written as a sum of positive squares in only one way, i.e., 78057225 + 236196 = 8835^2 + 486^2 .

It is not a de Polignac number, because 78293421 - 2¹ = 78293419 is a prime.

It is a super-2 number, since 2×78293421² = 12259719543766482, 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 (78293401) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4349626 + ... + 4349643.

Almost surely, 2^78293421 is an apocalyptic number.

It is an amenable number.

78293421 is a deficient number, since it is larger than the sum of its proper divisors (34797089).

78293421 is a wasteful number, since it uses less digits than its factorization.

78293421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8699275 (or 8699272 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 78293421 is about 8848.3569661265. The cubic root of 78293421 is about 427.8009617664.

The spelling of 78293421 in words is "seventy-eight million, two hundred ninety-three thousand, four hundred twenty-one".