421820681 has 4 divisors (see below), whose sum is σ = 424151364. Its totient is φ = 419490000.

The previous prime is 421820657. The next prime is 421820687. The reversal of 421820681 is 186028124.

It is a happy number.

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 87516025 + 334304656 = 9355^2 + 18284^2 .

It is a cyclic number.

It is not a de Polignac number, because 421820681 - 2¹⁴ = 421804297 is a prime.

It is a super-2 number, since 2×421820681² = 355865373838607522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421820687) 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, 1165070 + ... + 1165431.

It is an arithmetic number, because the mean of its divisors is an integer number (106037841).

Almost surely, 2^421820681 is an apocalyptic number.

It is an amenable number.

421820681 is a deficient number, since it is larger than the sum of its proper divisors (2330683).

421820681 is a wasteful number, since it uses less digits than its factorization.

421820681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2330682.

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 421820681 is about 20538.2735642507. The cubic root of 421820681 is about 749.9678095814.

The spelling of 421820681 in words is "four hundred twenty-one million, eight hundred twenty thousand, six hundred eighty-one".