21890154 has 64 divisors (see below), whose sum is σ = 53157888. Its totient is φ = 5918400.

The previous prime is 21890149. The next prime is 21890159. The reversal of 21890154 is 45109812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21890149) and next prime (21890159).

It is not an unprimeable number, because it can be changed into a prime (21890159) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26187 + ... + 27009.

It is an arithmetic number, because the mean of its divisors is an integer number (830592).

Almost surely, 2^21890154 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21890154, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26578944).

21890154 is an abundant number, since it is smaller than the sum of its proper divisors (31267734).

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

21890154 is a wasteful number, since it uses less digits than its factorization.

21890154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 21890154 is about 4678.6914837377. The cubic root of 21890154 is about 279.7368019930.

Adding to 21890154 its reverse (45109812), we get a palindrome (66999966).

The spelling of 21890154 in words is "twenty-one million, eight hundred ninety thousand, one hundred fifty-four".