67136921 has 4 divisors (see below), whose sum is σ = 67157172. Its totient is φ = 67116672.

The previous prime is 67136903. The next prime is 67136933. The reversal of 67136921 is 12963176.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38887696 + 28249225 = 6236^2 + 5315^2 .

It is a cyclic number.

It is not a de Polignac number, because 67136921 - 2⁶ = 67136857 is a prime.

It is a super-2 number, since 2×67136921² = 9014732322720482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67136521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3860 + ... + 12213.

It is an arithmetic number, because the mean of its divisors is an integer number (16789293).

Almost surely, 2^67136921 is an apocalyptic number.

It is an amenable number.

67136921 is a deficient number, since it is larger than the sum of its proper divisors (20251).

67136921 is a wasteful number, since it uses less digits than its factorization.

67136921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20250.

The product of its digits is 13608, while the sum is 35.

The square root of 67136921 is about 8193.7122844288. The cubic root of 67136921 is about 406.4312940419.

The spelling of 67136921 in words is "sixty-seven million, one hundred thirty-six thousand, nine hundred twenty-one".