67421561 has 4 divisors (see below), whose sum is σ = 67519824. Its totient is φ = 67323300.

The previous prime is 67421539. The next prime is 67421567. The reversal of 67421561 is 16512476.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 67421561 - 2²² = 63227257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67421567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48095 + ... + 49476.

It is an arithmetic number, because the mean of its divisors is an integer number (16879956).

Almost surely, 2^67421561 is an apocalyptic number.

It is an amenable number.

67421561 is a deficient number, since it is larger than the sum of its proper divisors (98263).

67421561 is an equidigital number, since it uses as much as digits as its factorization.

67421561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98262.

The product of its digits is 10080, while the sum is 32.

The square root of 67421561 is about 8211.0633294355. The cubic root of 67421561 is about 407.0048656519.

The spelling of 67421561 in words is "sixty-seven million, four hundred twenty-one thousand, five hundred sixty-one".