421921836 has 72 divisors (see below), whose sum is σ = 1221153024. Its totient is φ = 120324960.

The previous prime is 421921763. The next prime is 421921849. The reversal of 421921836 is 638129124.

It is a super-2 number, since 2×421921836² = 356036071387221792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 421921836.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 172921 + ... + 175343.

Almost surely, 2^421921836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 421921836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (610576512).

421921836 is an abundant number, since it is smaller than the sum of its proper divisors (799231188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

421921836 is a wasteful number, since it uses less digits than its factorization.

421921836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3131 (or 3126 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 421921836 is about 20540.7360140770. The cubic root of 421921836 is about 750.0277536396.

The spelling of 421921836 in words is "four hundred twenty-one million, nine hundred twenty-one thousand, eight hundred thirty-six".