406021997 has 4 divisors (see below), whose sum is σ = 406062300. Its totient is φ = 405981696.

The previous prime is 406021991. The next prime is 406022027. The reversal of 406021997 is 799120604.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 91278916 + 314743081 = 9554^2 + 17741^2 .

It is a cyclic number.

It is not a de Polignac number, because 406021997 - 2⁶ = 406021933 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 406021997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (406021991) 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, 9773 + ... + 30125.

It is an arithmetic number, because the mean of its divisors is an integer number (101515575).

Almost surely, 2^406021997 is an apocalyptic number.

It is an amenable number.

406021997 is a deficient number, since it is larger than the sum of its proper divisors (40303).

406021997 is a wasteful number, since it uses less digits than its factorization.

406021997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40302.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 406021997 is about 20149.9875186066. The cubic root of 406021997 is about 740.4854356875.

The spelling of 406021997 in words is "four hundred six million, twenty-one thousand, nine hundred ninety-seven".