21172402 has 8 divisors (see below), whose sum is σ = 32232816. Its totient is φ = 10428132.

The previous prime is 21172381. The next prime is 21172423. The reversal of 21172402 is 20427112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21172381) and next prime (21172423).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21172402.

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, 78868 + ... + 79135.

It is an arithmetic number, because the mean of its divisors is an integer number (4029102).

Almost surely, 2^21172402 is an apocalyptic number.

21172402 is a deficient number, since it is larger than the sum of its proper divisors (11060414).

21172402 is a wasteful number, since it uses less digits than its factorization.

21172402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158072.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21172402 is about 4601.3478460121. The cubic root of 21172402 is about 276.6453514973.

Adding to 21172402 its reverse (20427112), we get a palindrome (41599514).

The spelling of 21172402 in words is "twenty-one million, one hundred seventy-two thousand, four hundred two".