21878254 has 4 divisors (see below), whose sum is σ = 32817384. Its totient is φ = 10939126.

The previous prime is 21878251. The next prime is 21878257. The reversal of 21878254 is 45287812.

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

It is an interprime number because it is at equal distance from previous prime (21878251) and next prime (21878257).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21878251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5469562 + ... + 5469565.

It is an arithmetic number, because the mean of its divisors is an integer number (8204346).

Almost surely, 2^21878254 is an apocalyptic number.

21878254 is a deficient number, since it is larger than the sum of its proper divisors (10939130).

21878254 is a wasteful number, since it uses less digits than its factorization.

21878254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10939129.

The product of its digits is 35840, while the sum is 37.

The square root of 21878254 is about 4677.4195877642. The cubic root of 21878254 is about 279.6861023140.

The spelling of 21878254 in words is "twenty-one million, eight hundred seventy-eight thousand, two hundred fifty-four".