151531021 has 8 divisors (see below), whose sum is σ = 156423960. Its totient is φ = 146680128.

The previous prime is 151530983. The next prime is 151531027. The reversal of 151531021 is 120135151.

It can be written as a sum of positive squares in 4 ways, for example, as 127373796 + 24157225 = 11286^2 + 4915^2 .

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 151531021 - 2¹⁷ = 151399949 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 151531021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (151531027) 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, 3106 + ... + 17683.

It is an arithmetic number, because the mean of its divisors is an integer number (19552995).

Almost surely, 2^151531021 is an apocalyptic number.

It is an amenable number.

151531021 is a deficient number, since it is larger than the sum of its proper divisors (4892939).

151531021 is a wasteful number, since it uses less digits than its factorization.

151531021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21023.

The product of its (nonzero) digits is 150, while the sum is 19.

The square root of 151531021 is about 12309.7937025768. The cubic root of 151531021 is about 533.1308939590.

Adding to 151531021 its reverse (120135151), we get a palindrome (271666172).

The spelling of 151531021 in words is "one hundred fifty-one million, five hundred thirty-one thousand, twenty-one".