21234567898 has 4 divisors (see below), whose sum is σ = 31851851850. Its totient is φ = 10617283948.

The previous prime is 21234567889. The next prime is 21234567919. The reversal of 21234567898 is 89876543212.

21234567898 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16222352689 + 5012215209 = 127367^2 + 70797^2 .

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is an upside-down number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5308641973 + ... + 5308641976.

Almost surely, 2^21234567898 is an apocalyptic number.

21234567898 is a deficient number, since it is larger than the sum of its proper divisors (10617283952).

21234567898 is a wasteful number, since it uses less digits than its factorization.

21234567898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10617283951.

The product of its digits is 5806080, while the sum is 55.

The spelling of 21234567898 in words is "twenty-one billion, two hundred thirty-four million, five hundred sixty-seven thousand, eight hundred ninety-eight".