1021531 has 4 divisors (see below), whose sum is σ = 1167472. Its totient is φ = 875592.

The previous prime is 1021487. The next prime is 1021541. The reversal of 1021531 is 1351201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1351201 = 71 ⋅19031.

It is a cyclic number.

It is not a de Polignac number, because 1021531 - 2⁷ = 1021403 is a prime.

It is a super-2 number, since 2×1021531² = 2087051167922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021541) 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 3 ways as a sum of consecutive naturals, for example, 72960 + ... + 72973.

It is an arithmetic number, because the mean of its divisors is an integer number (291868).

2^1021531 is an apocalyptic number.

1021531 is a deficient number, since it is larger than the sum of its proper divisors (145941).

1021531 is an equidigital number, since it uses as much as digits as its factorization.

1021531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145940.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 1021531 is about 1010.7081675736. The cubic root of 1021531 is about 100.7126098102.

Adding to 1021531 its reverse (1351201), we get a palindrome (2372732).

The spelling of 1021531 in words is "one million, twenty-one thousand, five hundred thirty-one".