151001221 has 4 divisors (see below), whose sum is σ = 172572832. Its totient is φ = 129429612.

The previous prime is 151001209. The next prime is 151001239. The reversal of 151001221 is 122100151.

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 an emirpimes, since its reverse is a distinct semiprime: 122100151 = 1301 ⋅93851.

It is a cyclic number.

It is not a de Polignac number, because 151001221 - 2¹⁹ = 150476933 is a prime.

It is a Duffinian number.

151001221 is a modest number, since divided by 1221 gives 151 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (151001261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10785795 + ... + 10785808.

It is an arithmetic number, because the mean of its divisors is an integer number (43143208).

Almost surely, 2^151001221 is an apocalyptic number.

It is an amenable number.

151001221 is a deficient number, since it is larger than the sum of its proper divisors (21571611).

151001221 is an equidigital number, since it uses as much as digits as its factorization.

151001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21571610.

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 151001221 is about 12288.2554091295. The cubic root of 151001221 is about 532.5088374590.

Adding to 151001221 its reverse (122100151), we get a palindrome (273101372).

The spelling of 151001221 in words is "one hundred fifty-one million, one thousand, two hundred twenty-one".