1264660221 has 64 divisors (see below), whose sum is σ = 2017198080. Its totient is φ = 696696000.

The previous prime is 1264660207. The next prime is 1264660223. The reversal of 1264660221 is 1220664621.

It is not a de Polignac number, because 1264660221 - 2⁶ = 1264660157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1264660223) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1387756 + ... + 1388666.

It is an arithmetic number, because the mean of its divisors is an integer number (31518720).

Almost surely, 2^1264660221 is an apocalyptic number.

1264660221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1264660221 is a deficient number, since it is larger than the sum of its proper divisors (752537859).

1264660221 is a wasteful number, since it uses less digits than its factorization.

1264660221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 1264660221 is about 35562.0615403551. The cubic root of 1264660221 is about 1081.4122531254.

The spelling of 1264660221 in words is "one billion, two hundred sixty-four million, six hundred sixty thousand, two hundred twenty-one".