78275421 has 24 divisors (see below), whose sum is σ = 136019520. Its totient is φ = 42374016.

The previous prime is 78275419. The next prime is 78275423. The reversal of 78275421 is 12457287.

It is an interprime number because it is at equal distance from previous prime (78275419) and next prime (78275423).

It is not a de Polignac number, because 78275421 - 2¹ = 78275419 is a prime.

It is a super-2 number, since 2×78275421² = 12254083065454482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78275423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31500 + ... + 33893.

It is an arithmetic number, because the mean of its divisors is an integer number (5667480).

Almost surely, 2^78275421 is an apocalyptic number.

It is an amenable number.

78275421 is a deficient number, since it is larger than the sum of its proper divisors (57744099).

78275421 is a wasteful number, since it uses less digits than its factorization.

78275421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65425 (or 65422 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 78275421 is about 8847.3397696709. The cubic root of 78275421 is about 427.7681748161.

The spelling of 78275421 in words is "seventy-eight million, two hundred seventy-five thousand, four hundred twenty-one".