212400004021 has 4 divisors (see below), whose sum is σ = 212781333132. Its totient is φ = 212018674912.

The previous prime is 212400003947. The next prime is 212400004027. The reversal of 212400004021 is 120400004212.

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 82147584996 + 130252419025 = 286614^2 + 360905^2 .

It is a cyclic number.

It is not a de Polignac number, because 212400004021 - 2³⁵ = 178040265653 is a prime.

It is a super-2 number, since 2×212400004021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212400003986 and 212400004004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212400004027) 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, 190663720 + ... + 190664833.

It is an arithmetic number, because the mean of its divisors is an integer number (53195333283).

Almost surely, 2^212400004021 is an apocalyptic number.

It is an amenable number.

212400004021 is a deficient number, since it is larger than the sum of its proper divisors (381329111).

212400004021 is an equidigital number, since it uses as much as digits as its factorization.

212400004021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381329110.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 212400004021 its reverse (120400004212), we get a palindrome (332800008233).

The spelling of 212400004021 in words is "two hundred twelve billion, four hundred million, four thousand, twenty-one".