1257221730 has 16 divisors (see below), whose sum is σ = 3017332224. Its totient is φ = 335259120.

The previous prime is 1257221711. The next prime is 1257221741. The reversal of 1257221730 is 371227521.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 41907391 = 1257221730 / (1 + 2 + 5 + 7 + 2 + 2 + 1 + 7 + 3 + 0).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20953666 + ... + 20953725.

It is an arithmetic number, because the mean of its divisors is an integer number (188583264).

Almost surely, 2^1257221730 is an apocalyptic number.

1257221730 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1257221730 is an abundant number, since it is smaller than the sum of its proper divisors (1760110494).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1257221730 is a wasteful number, since it uses less digits than its factorization.

1257221730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41907401.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 1257221730 is about 35457.3226569633. The cubic root of 1257221730 is about 1079.2878621475.

The spelling of 1257221730 in words is "one billion, two hundred fifty-seven million, two hundred twenty-one thousand, seven hundred thirty".