67921621 has 4 divisors (see below), whose sum is σ = 67957792. Its totient is φ = 67885452.

The previous prime is 67921583. The next prime is 67921643. The reversal of 67921621 is 12612976.

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 67921621 - 2⁷ = 67921493 is a prime.

It is a super-2 number, since 2×67921621² = 9226693198535282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67921421) 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, 15105 + ... + 19078.

It is an arithmetic number, because the mean of its divisors is an integer number (16989448).

Almost surely, 2^67921621 is an apocalyptic number.

It is an amenable number.

67921621 is a deficient number, since it is larger than the sum of its proper divisors (36171).

67921621 is a wasteful number, since it uses less digits than its factorization.

67921621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36170.

The product of its digits is 9072, while the sum is 34.

The square root of 67921621 is about 8241.4574560572. The cubic root of 67921621 is about 408.0086283098.

The spelling of 67921621 in words is "sixty-seven million, nine hundred twenty-one thousand, six hundred twenty-one".