1231000021001 has 4 divisors (see below), whose sum is σ = 1239856136400. Its totient is φ = 1222143905604.

The previous prime is 1231000020979. The next prime is 1231000021003. The reversal of 1231000021001 is 1001200001321.

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 a cyclic number.

It is not a de Polignac number, because 1231000021001 - 2⁶ = 1231000020937 is a prime.

It is a super-2 number, since 2×1231000021001² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231000021003) 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, 4428057491 + ... + 4428057768.

It is an arithmetic number, because the mean of its divisors is an integer number (309964034100).

Almost surely, 2^{1231000021001} is an apocalyptic number.

It is an amenable number.

1231000021001 is a deficient number, since it is larger than the sum of its proper divisors (8856115399).

1231000021001 is an equidigital number, since it uses as much as digits as its factorization.

1231000021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8856115398.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 1231000021001 its reverse (1001200001321), we get a palindrome (2232200022322).

The spelling of 1231000021001 in words is "one trillion, two hundred thirty-one billion, twenty-one thousand, one".