21673398 has 8 divisors (see below), whose sum is σ = 43346808. Its totient is φ = 7224464.

The previous prime is 21673387. The next prime is 21673409. The reversal of 21673398 is 89337612.

It is an interprime number because it is at equal distance from previous prime (21673387) and next prime (21673409).

It is a sphenic number, since it is the product of 3 distinct primes.

21673398 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1806111 + ... + 1806122.

It is an arithmetic number, because the mean of its divisors is an integer number (5418351).

Almost surely, 2^21673398 is an apocalyptic number.

21673398 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21673398 is a wasteful number, since it uses less digits than its factorization.

21673398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3612238.

The product of its digits is 54432, while the sum is 39.

The square root of 21673398 is about 4655.4696862937. The cubic root of 21673398 is about 278.8104209215.

It can be divided in two parts, 2167 and 3398, that added together give a triangular number (5565 = T₁₀₅).

The spelling of 21673398 in words is "twenty-one million, six hundred seventy-three thousand, three hundred ninety-eight".