67729481921 has 4 divisors (see below), whose sum is σ = 67730065200. Its totient is φ = 67728898644.

The previous prime is 67729481891. The next prime is 67729481923. The reversal of 67729481921 is 12918492776.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 67729481921 - 2¹⁸ = 67729219777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67729481923) 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, 51611 + ... + 371648.

It is an arithmetic number, because the mean of its divisors is an integer number (16932516300).

Almost surely, 2^67729481921 is an apocalyptic number.

It is an amenable number.

67729481921 is a deficient number, since it is larger than the sum of its proper divisors (583279).

67729481921 is a wasteful number, since it uses less digits than its factorization.

67729481921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583278.

The product of its digits is 3048192, while the sum is 56.

The spelling of 67729481921 in words is "sixty-seven billion, seven hundred twenty-nine million, four hundred eighty-one thousand, nine hundred twenty-one".