2001221212157 has 2 divisors, whose sum is σ = 2001221212158. Its totient is φ = 2001221212156.

The previous prime is 2001221212117. The next prime is 2001221212217. The reversal of 2001221212157 is 7512121221002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1984072262041 + 17148950116 = 1408571^2 + 130954^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001221212157 - 2¹² = 2001221208061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001221212117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000610606078 + 1000610606079.

It is an arithmetic number, because the mean of its divisors is an integer number (1000610606079).

Almost surely, 2^{2001221212157} is an apocalyptic number.

It is an amenable number.

2001221212157 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001221212157 is an equidigital number, since it uses as much as digits as its factorization.

2001221212157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1120, while the sum is 26.

Adding to 2001221212157 its reverse (7512121221002), we get a palindrome (9513342433159).

The spelling of 2001221212157 in words is "two trillion, one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred fifty-seven".