21420104 has 8 divisors (see below), whose sum is σ = 40162710. Its totient is φ = 10710048.

The previous prime is 21420103. The next prime is 21420121. The reversal of 21420104 is 40102412.

It can be written as a sum of positive squares in only one way, i.e., 20232004 + 1188100 = 4498^2 + 1090^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21420103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1338749 + ... + 1338764.

Almost surely, 2^21420104 is an apocalyptic number.

It is an amenable number.

21420104 is a deficient number, since it is larger than the sum of its proper divisors (18742606).

21420104 is a wasteful number, since it uses less digits than its factorization.

21420104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2677519 (or 2677515 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21420104 is about 4628.1858216800. The cubic root of 21420104 is about 277.7200224576.

Adding to 21420104 its reverse (40102412), we get a palindrome (61522516).

The spelling of 21420104 in words is "twenty-one million, four hundred twenty thousand, one hundred four".