1266479721 has 24 divisors (see below), whose sum is σ = 1971938696. Its totient is φ = 778636800.

The previous prime is 1266479717. The next prime is 1266479741. The reversal of 1266479721 is 1279746621.

It can be written as a sum of positive squares in 4 ways, for example, as 47073321 + 1219406400 = 6861^2 + 34920^2 .

It is not a de Polignac number, because 1266479721 - 2² = 1266479717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1266479741) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136011 + ... + 145023.

Almost surely, 2^1266479721 is an apocalyptic number.

It is an amenable number.

1266479721 is a deficient number, since it is larger than the sum of its proper divisors (705458975).

1266479721 is a wasteful number, since it uses less digits than its factorization.

1266479721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10233 (or 10230 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 1266479721 is about 35587.6343833079. The cubic root of 1266479721 is about 1081.9306233798.

The spelling of 1266479721 in words is "one billion, two hundred sixty-six million, four hundred seventy-nine thousand, seven hundred twenty-one".