402087221 has 4 divisors (see below), whose sum is σ = 402266700. Its totient is φ = 401907744.

The previous prime is 402087199. The next prime is 402087223. The reversal of 402087221 is 122780204.

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 110019121 + 292068100 = 10489^2 + 17090^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-402087221 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 (402087223) 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, 86336 + ... + 90873.

It is an arithmetic number, because the mean of its divisors is an integer number (100566675).

Almost surely, 2^402087221 is an apocalyptic number.

It is an amenable number.

402087221 is a deficient number, since it is larger than the sum of its proper divisors (179479).

402087221 is a wasteful number, since it uses less digits than its factorization.

402087221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179478.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 402087221 is about 20052.1126318401. The cubic root of 402087221 is about 738.0856417285.

The spelling of 402087221 in words is "four hundred two million, eighty-seven thousand, two hundred twenty-one".