202156021 has 4 divisors (see below), whose sum is σ = 202650700. Its totient is φ = 201661344.

The previous prime is 202155979. The next prime is 202156033. The reversal of 202156021 is 120651202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 162843121 + 39312900 = 12761^2 + 6270^2 .

It is a cyclic number.

It is not a de Polignac number, because 202156021 - 2²¹ = 200058869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 202156021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202156121) 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, 246726 + ... + 247543.

It is an arithmetic number, because the mean of its divisors is an integer number (50662675).

Almost surely, 2^202156021 is an apocalyptic number.

It is an amenable number.

202156021 is a deficient number, since it is larger than the sum of its proper divisors (494679).

202156021 is an equidigital number, since it uses as much as digits as its factorization.

202156021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494678.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 202156021 is about 14218.1581437259. The cubic root of 202156021 is about 586.8974559364.

The spelling of 202156021 in words is "two hundred two million, one hundred fifty-six thousand, twenty-one".