21949087 has 2 divisors, whose sum is σ = 21949088. Its totient is φ = 21949086.

The previous prime is 21949069. The next prime is 21949093. The reversal of 21949087 is 78094912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21949087 - 2¹⁵ = 21916319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21949097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10974543 + 10974544.

It is an arithmetic number, because the mean of its divisors is an integer number (10974544).

Almost surely, 2^21949087 is an apocalyptic number.

21949087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21949087 is an equidigital number, since it uses as much as digits as its factorization.

21949087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 21949087 is about 4684.9852721220. The cubic root of 21949087 is about 279.9876142480.

The spelling of 21949087 in words is "twenty-one million, nine hundred forty-nine thousand, eighty-seven".