1210021001 has 4 divisors (see below), whose sum is σ = 1382881152. Its totient is φ = 1037160852.

The previous prime is 1210020967. The next prime is 1210021009. The reversal of 1210021001 is 1001200121.

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: 1001200121 = 2663 ⋅375967.

It is not a de Polignac number, because 1210021001 - 2¹⁰ = 1210019977 is a prime.

It is a super-2 number, since 2×1210021001² = 2928301645722084002, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1210021001.

It is not an unprimeable number, because it can be changed into a prime (1210021009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86430065 + ... + 86430078.

It is an arithmetic number, because the mean of its divisors is an integer number (345720288).

Almost surely, 2^1210021001 is an apocalyptic number.

It is an amenable number.

1210021001 is a deficient number, since it is larger than the sum of its proper divisors (172860151).

1210021001 is an equidigital number, since it uses as much as digits as its factorization.

1210021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172860150.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1210021001 is about 34785.3561286930. The cubic root of 1210021001 is about 1065.6084016655.

Adding to 1210021001 its reverse (1001200121), we get a palindrome (2211221122).

The spelling of 1210021001 in words is "one billion, two hundred ten million, twenty-one thousand, one".