21890351 has 16 divisors (see below), whose sum is σ = 25945920. Its totient is φ = 18078720.

The previous prime is 21890329. The next prime is 21890369. The reversal of 21890351 is 15309812.

It is a cyclic number.

It is not a de Polignac number, because 21890351 - 2¹⁰ = 21889327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21890651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25115 + ... + 25971.

It is an arithmetic number, because the mean of its divisors is an integer number (1621620).

Almost surely, 2^21890351 is an apocalyptic number.

21890351 is a deficient number, since it is larger than the sum of its proper divisors (4055569).

21890351 is an equidigital number, since it uses as much as digits as its factorization.

21890351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 21890351 is about 4678.7125365853. The cubic root of 21890351 is about 279.7376411524.

The spelling of 21890351 in words is "twenty-one million, eight hundred ninety thousand, three hundred fifty-one".