1278021630 has 16 divisors (see below), whose sum is σ = 3067251984. Its totient is φ = 340805760.

The previous prime is 1278021623. The next prime is 1278021671. The reversal of 1278021630 is 361208721.

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: 42600721 = 1278021630 / (1 + 2 + 7 + 8 + 0 + 2 + 1 + 6 + 3 + 0).

It is a congruent 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, 21300331 + ... + 21300390.

It is an arithmetic number, because the mean of its divisors is an integer number (191703249).

Almost surely, 2^1278021630 is an apocalyptic number.

1278021630 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1278021630 is an abundant number, since it is smaller than the sum of its proper divisors (1789230354).

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

1278021630 is a wasteful number, since it uses less digits than its factorization.

1278021630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42600731.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 1278021630 is about 35749.4283870386. The cubic root of 1278021630 is about 1085.2073704455.

The spelling of 1278021630 in words is "one billion, two hundred seventy-eight million, twenty-one thousand, six hundred thirty".