10621981 has 2 divisors, whose sum is σ = 10621982. Its totient is φ = 10621980.

The previous prime is 10621973. The next prime is 10621999. The reversal of 10621981 is 18912601.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10621081 + 900 = 3259^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 10621981 - 2³ = 10621973 is a prime.

It is a super-2 number, since 2×10621981² = 225652960728722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10621181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5310990 + 5310991.

It is an arithmetic number, because the mean of its divisors is an integer number (5310991).

Almost surely, 2^10621981 is an apocalyptic number.

It is an amenable number.

10621981 is a deficient number, since it is larger than the sum of its proper divisors (1).

10621981 is an equidigital number, since it uses as much as digits as its factorization.

10621981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 10621981 is about 3259.1380762404. The cubic root of 10621981 is about 219.8206596295.

The spelling of 10621981 in words is "ten million, six hundred twenty-one thousand, nine hundred eighty-one".