216862421 has 12 divisors (see below), whose sum is σ = 231034692. Its totient is φ = 203516928.

The previous prime is 216862417. The next prime is 216862433. The reversal of 216862421 is 124268612.

216862421 = 1² + 2² + ... + 866².

It can be written as a sum of positive squares in 6 ways, for example, as 448900 + 216413521 = 670^2 + 14711^2 .

It is not a de Polignac number, because 216862421 - 2² = 216862417 is a prime.

It is a super-3 number, since 3×216862421³ (a number of 26 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216862721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 124271 + ... + 126003.

It is an arithmetic number, because the mean of its divisors is an integer number (19252891).

Almost surely, 2^216862421 is an apocalyptic number.

It is an amenable number.

216862421 is a deficient number, since it is larger than the sum of its proper divisors (14172271).

216862421 is a wasteful number, since it uses less digits than its factorization.

216862421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200 (or 2183 counting only the distinct ones).

The product of its digits is 9216, while the sum is 32.

The square root of 216862421 is about 14726.2493867244. The cubic root of 216862421 is about 600.7974775426.

The spelling of 216862421 in words is "two hundred sixteen million, eight hundred sixty-two thousand, four hundred twenty-one".