70921 has 2 divisors, whose sum is σ = 70922. Its totient is φ = 70920.

The previous prime is 70919. The next prime is 70937. The reversal of 70921 is 12907.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69696 + 1225 = 264^2 + 35^2 .

It is an emirp because it is prime and its reverse (12907) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 70921 - 2¹ = 70919 is a prime.

Together with 70919, it forms a pair of twin primes.

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 14.

It is not a weakly prime, because it can be changed into another prime (70901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35460 + 35461.

It is an arithmetic number, because the mean of its divisors is an integer number (35461).

2⁷⁰⁹²¹ is an apocalyptic number.

It is an amenable number.

70921 is a deficient number, since it is larger than the sum of its proper divisors (1).

70921 is an equidigital number, since it uses as much as digits as its factorization.

70921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 19.

The square root of 70921 is about 266.3099697721. The cubic root of 70921 is about 41.3928138320.

The spelling of 70921 in words is "seventy thousand, nine hundred twenty-one".