21950781 has 4 divisors (see below), whose sum is σ = 29267712. Its totient is φ = 14633852.

The previous prime is 21950779. The next prime is 21950783. The reversal of 21950781 is 18705912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21950779) and next prime (21950783).

It is a cyclic number.

It is not a de Polignac number, because 21950781 - 2¹ = 21950779 is a prime.

It is a super-2 number, since 2×21950781² = 963673573019922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21950783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3658461 + ... + 3658466.

It is an arithmetic number, because the mean of its divisors is an integer number (7316928).

Almost surely, 2^21950781 is an apocalyptic number.

It is an amenable number.

21950781 is a deficient number, since it is larger than the sum of its proper divisors (7316931).

21950781 is an equidigital number, since it uses as much as digits as its factorization.

21950781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7316930.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 21950781 is about 4685.1660589567. The cubic root of 21950781 is about 279.9948170809.

The spelling of 21950781 in words is "twenty-one million, nine hundred fifty thousand, seven hundred eighty-one".