9902620866649 has 9 divisors (see below), whose sum is σ = 11519400918207. Its totient is φ = 8487941861784.

The previous prime is 9902620866641. The next prime is 9902620866667. The reversal of 9902620866649 is 9466680262099.

The square root of 9902620866649 is 3146843.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 6977221122249 + 2925399744400 = 2641443^2 + 1710380^2 .

It is not a de Polignac number, because 9902620866649 - 2³ = 9902620866641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9902620866641) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 21803127 + ... + 22252675.

Almost surely, 2^{9902620866649} is an apocalyptic number.

9902620866649 is the 3146843-rd square number.

9902620866649 is the 1573422-nd centered octagonal number.

It is an amenable number.

9902620866649 is a deficient number, since it is larger than the sum of its proper divisors (1616780051558).

9902620866649 is an frugal number, since it uses more digits than its factorization.

9902620866649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 899112 (or 449556 counting only the distinct ones).

The product of its (nonzero) digits is 120932352, while the sum is 67.

The spelling of 9902620866649 in words is "nine trillion, nine hundred two billion, six hundred twenty million, eight hundred sixty-six thousand, six hundred forty-nine".