216421040 has 80 divisors (see below), whose sum is σ = 551321856. Its totient is φ = 78355200.

The previous prime is 216421031. The next prime is 216421087. The reversal of 216421040 is 40124612.

216421040 = T₃₆₁ + T₃₆₂ + ... + T₁₁₀₃.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 290909 + ... + 291651.

Almost surely, 2^216421040 is an apocalyptic number.

216421040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216421040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (275660928).

216421040 is an abundant number, since it is smaller than the sum of its proper divisors (334900816).

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

216421040 is a wasteful number, since it uses less digits than its factorization.

216421040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1098 (or 1092 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 216421040 is about 14711.2555548464. The cubic root of 216421040 is about 600.3895988184.

Adding to 216421040 its reverse (40124612), we get a palindrome (256545652).

The spelling of 216421040 in words is "two hundred sixteen million, four hundred twenty-one thousand, forty".