7497678999721 has 9 divisors (see below), whose sum is σ = 7567397348133. Its totient is φ = 7428597229440.

The previous prime is 7497678999709. The next prime is 7497678999739. The reversal of 7497678999721 is 1279998767947.

The square root of 7497678999721 is 2738189.

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

It can be written as a sum of positive squares in 4 ways, for example, as 182276909721 + 7315402090000 = 426939^2 + 2704700^2 .

It is not a de Polignac number, because 7497678999721 - 2¹³ = 7497678991529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7497678999751) 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, 298450041 + ... + 298475161.

Almost surely, 2^{7497678999721} is an apocalyptic number.

7497678999721 is the 2738189-th square number.

7497678999721 is the 1369095-th centered octagonal number.

It is an amenable number.

7497678999721 is a deficient number, since it is larger than the sum of its proper divisors (69718348412).

7497678999721 is an frugal number, since it uses more digits than its factorization.

7497678999721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50460 (or 25230 counting only the distinct ones).

The product of its digits is 6049137024, while the sum is 85.

The spelling of 7497678999721 in words is "seven trillion, four hundred ninety-seven billion, six hundred seventy-eight million, nine hundred ninety-nine thousand, seven hundred twenty-one".