212021021997 has 6 divisors (see below), whose sum is σ = 306252587342. Its totient is φ = 141347347992.

The previous prime is 212021021951. The next prime is 212021022001. The reversal of 212021021997 is 799120120212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 210686508036 + 1334513961 = 459006^2 + 36531^2 .

It is not a de Polignac number, because 212021021997 - 2⁸ = 212021021741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212021021297) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11778945658 + ... + 11778945675.

Almost surely, 2^212021021997 is an apocalyptic number.

It is an amenable number.

212021021997 is a deficient number, since it is larger than the sum of its proper divisors (94231565345).

212021021997 is a wasteful number, since it uses less digits than its factorization.

212021021997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23557891339 (or 23557891336 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The spelling of 212021021997 in words is "two hundred twelve billion, twenty-one million, twenty-one thousand, nine hundred ninety-seven".