1397651820 has 24 divisors (see below), whose sum is σ = 3913425264. Its totient is φ = 372707136.

The previous prime is 1397651809. The next prime is 1397651851. The reversal of 1397651820 is 281567931.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11647039 + ... + 11647158.

It is an arithmetic number, because the mean of its divisors is an integer number (163059386).

Almost surely, 2^1397651820 is an apocalyptic number.

1397651820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1397651820 is an abundant number, since it is smaller than the sum of its proper divisors (2515773444).

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

1397651820 is a wasteful number, since it uses less digits than its factorization.

1397651820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23294209 (or 23294207 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 1397651820 is about 37385.1818238189. The cubic root of 1397651820 is about 1118.0631437396.

The spelling of 1397651820 in words is "one billion, three hundred ninety-seven million, six hundred fifty-one thousand, eight hundred twenty".