163521421 has 8 divisors (see below), whose sum is σ = 195007104. Its totient is φ = 134067120.

The previous prime is 163521409. The next prime is 163521427. The reversal of 163521421 is 124125361.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 163521421 - 2²⁷ = 29303693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163521427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 507670 + ... + 507991.

It is an arithmetic number, because the mean of its divisors is an integer number (24375888).

Almost surely, 2^163521421 is an apocalyptic number.

It is an amenable number.

163521421 is a deficient number, since it is larger than the sum of its proper divisors (31485683).

163521421 is a wasteful number, since it uses less digits than its factorization.

163521421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1015691.

The product of its digits is 1440, while the sum is 25.

The square root of 163521421 is about 12787.5494524948. The cubic root of 163521421 is about 546.8374097743.

Adding to 163521421 its reverse (124125361), we get a palindrome (287646782).

The spelling of 163521421 in words is "one hundred sixty-three million, five hundred twenty-one thousand, four hundred twenty-one".