421666757 has 4 divisors (see below), whose sum is σ = 436207020. Its totient is φ = 407126496.

The previous prime is 421666747. The next prime is 421666771. The reversal of 421666757 is 757666124.

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 315453121 + 106213636 = 17761^2 + 10306^2 .

It is a cyclic number.

It is not a de Polignac number, because 421666757 - 2⁴ = 421666741 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 (421666717) 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, 7270088 + ... + 7270145.

It is an arithmetic number, because the mean of its divisors is an integer number (109051755).

Almost surely, 2^421666757 is an apocalyptic number.

It is an amenable number.

421666757 is a deficient number, since it is larger than the sum of its proper divisors (14540263).

421666757 is a wasteful number, since it uses less digits than its factorization.

421666757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14540262.

The product of its digits is 423360, while the sum is 44.

The square root of 421666757 is about 20534.5259745629. The cubic root of 421666757 is about 749.8765764307.

The spelling of 421666757 in words is "four hundred twenty-one million, six hundred sixty-six thousand, seven hundred fifty-seven".