30400021 has 4 divisors (see below), whose sum is σ = 30898444. Its totient is φ = 29901600.

The previous prime is 30400003. The next prime is 30400031. The reversal of 30400021 is 12000403.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12000403 = 29 ⋅413807.

It can be written as a sum of positive squares in 2 ways, for example, as 1347921 + 29052100 = 1161^2 + 5390^2 .

It is a cyclic number.

It is not a de Polignac number, because 30400021 - 2¹⁷ = 30268949 is a prime.

It is a super-2 number, since 2×30400021² = 1848322553600882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 30399980 and 30400007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30400031) 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, 249120 + ... + 249241.

It is an arithmetic number, because the mean of its divisors is an integer number (7724611).

Almost surely, 2^30400021 is an apocalyptic number.

It is an amenable number.

30400021 is a deficient number, since it is larger than the sum of its proper divisors (498423).

30400021 is an equidigital number, since it uses as much as digits as its factorization.

30400021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498422.

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 30400021 is about 5513.6214052109. The cubic root of 30400021 is about 312.0982220063.

Adding to 30400021 its reverse (12000403), we get a palindrome (42400424).

The spelling of 30400021 in words is "thirty million, four hundred thousand, twenty-one".