1251021 has 4 divisors (see below), whose sum is σ = 1668032. Its totient is φ = 834012.

The previous prime is 1251011. The next prime is 1251037. The reversal of 1251021 is 1201521.

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.

It is not a de Polignac number, because 1251021 - 2¹⁷ = 1119949 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1250988 and 1251006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208501 + ... + 208506.

It is an arithmetic number, because the mean of its divisors is an integer number (417008).

2^1251021 is an apocalyptic number.

It is an amenable number.

1251021 is a deficient number, since it is larger than the sum of its proper divisors (417011).

1251021 is an equidigital number, since it uses as much as digits as its factorization.

1251021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417010.

The product of its (nonzero) digits is 20, while the sum is 12.

The square root of 1251021 is about 1118.4905006302. The cubic root of 1251021 is about 107.7510555575.

Adding to 1251021 its reverse (1201521), we get a palindrome (2452542).

The spelling of 1251021 in words is "one million, two hundred fifty-one thousand, twenty-one".