33400021 has 2 divisors, whose sum is σ = 33400022. Its totient is φ = 33400020.

The previous prime is 33399991. The next prime is 33400027. The reversal of 33400021 is 12000433.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32890225 + 509796 = 5735^2 + 714^2 .

It is an emirp because it is prime and its reverse (12000433) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-33400021 is a prime.

It is a super-2 number, since 2×33400021² = 2231122805600882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 33399974 and 33400010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33400027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16700010 + 16700011.

It is an arithmetic number, because the mean of its divisors is an integer number (16700011).

Almost surely, 2^33400021 is an apocalyptic number.

It is an amenable number.

33400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

33400021 is an equidigital number, since it uses as much as digits as its factorization.

33400021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 33400021 is about 5779.2751275571. The cubic root of 33400021 is about 322.0442726827.

Adding to 33400021 its reverse (12000433), we get a palindrome (45400454).

The spelling of 33400021 in words is "thirty-three million, four hundred thousand, twenty-one".