71428121 has 2 divisors, whose sum is σ = 71428122. Its totient is φ = 71428120.

The previous prime is 71428099. The next prime is 71428127. The reversal of 71428121 is 12182417.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68227600 + 3200521 = 8260^2 + 1789^2 .

It is a cyclic number.

It is not a de Polignac number, because 71428121 - 2²⁶ = 4319257 is a prime.

It is not a weakly prime, because it can be changed into another prime (71428127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35714060 + 35714061.

It is an arithmetic number, because the mean of its divisors is an integer number (35714061).

Almost surely, 2^71428121 is an apocalyptic number.

It is an amenable number.

71428121 is a deficient number, since it is larger than the sum of its proper divisors (1).

71428121 is an equidigital number, since it uses as much as digits as its factorization.

71428121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 896, while the sum is 26.

The square root of 71428121 is about 8451.5158995295. The cubic root of 71428121 is about 414.9123945336.

The spelling of 71428121 in words is "seventy-one million, four hundred twenty-eight thousand, one hundred twenty-one".