201436643421 has 20 divisors (see below), whose sum is σ = 324058571452. Its totient is φ = 123961010688.

The previous prime is 201436643351. The next prime is 201436643519. The reversal of 201436643421 is 124346634102.

201436643421 is a `hidden beast` number, since 2 + 0 + 1 + 4 + 3 + 6 + 643 + 4 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 138971638521 + 62465004900 = 372789^2 + 249930^2 .

It is not a de Polignac number, because 201436643421 - 2⁷ = 201436643293 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 (201436643021) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 95647876 + ... + 95649981.

Almost surely, 2^201436643421 is an apocalyptic number.

It is an amenable number.

201436643421 is a deficient number, since it is larger than the sum of its proper divisors (122621928031).

201436643421 is a wasteful number, since it uses less digits than its factorization.

201436643421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191297882 (or 191297873 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The spelling of 201436643421 in words is "two hundred one billion, four hundred thirty-six million, six hundred forty-three thousand, four hundred twenty-one".