156421921 has 8 divisors (see below), whose sum is σ = 162077760. Its totient is φ = 150866352.

The previous prime is 156421907. The next prime is 156421931. The reversal of 156421921 is 129124651.

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 156421921 - 2⁹ = 156421409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156421901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21885 + ... + 28138.

It is an arithmetic number, because the mean of its divisors is an integer number (20259720).

Almost surely, 2^156421921 is an apocalyptic number.

It is an amenable number.

156421921 is a deficient number, since it is larger than the sum of its proper divisors (5655839).

156421921 is an equidigital number, since it uses as much as digits as its factorization.

156421921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50135.

The product of its digits is 4320, while the sum is 31.

The square root of 156421921 is about 12506.8749494028. The cubic root of 156421921 is about 538.8061428026.

The spelling of 156421921 in words is "one hundred fifty-six million, four hundred twenty-one thousand, nine hundred twenty-one".