21420698 has 16 divisors (see below), whose sum is σ = 34995240. Its totient is φ = 9774336.

The previous prime is 21420683. The next prime is 21420703. The reversal of 21420698 is 89602412.

It can be written as a sum of positive squares in 4 ways, for example, as 5841889 + 15578809 = 2417^2 + 3947^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2315 + ... + 6942.

Almost surely, 2^21420698 is an apocalyptic number.

21420698 is a deficient number, since it is larger than the sum of its proper divisors (13574542).

21420698 is a wasteful number, since it uses less digits than its factorization.

21420698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9361.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21420698 is about 4628.2499932480. The cubic root of 21420698 is about 277.7225895813.

The spelling of 21420698 in words is "twenty-one million, four hundred twenty thousand, six hundred ninety-eight".