1397457620 has 54 divisors (see below), whose sum is σ = 3182718798. Its totient is φ = 515181888.

The previous prime is 1397457583. The next prime is 1397457661. The reversal of 1397457620 is 267547931.

It can be written as a sum of positive squares in 3 ways, for example, as 6615184 + 1390842436 = 2572^2 + 37294^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2173019 + ... + 2173661.

It is an arithmetic number, because the mean of its divisors is an integer number (58939237).

Almost surely, 2^1397457620 is an apocalyptic number.

1397457620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1397457620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1591359399).

1397457620 is an abundant number, since it is smaller than the sum of its proper divisors (1785261178).

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

1397457620 is an equidigital number, since it uses as much as digits as its factorization.

1397457620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1321 (or 663 counting only the distinct ones).

The product of its (nonzero) digits is 317520, while the sum is 44.

The square root of 1397457620 is about 37382.5844478415. The cubic root of 1397457620 is about 1118.0113573752.

Multiplying 1397457620 by its product of nonzero digits (317520), we get a square (443720743502400 = 21064680²).

The spelling of 1397457620 in words is "one billion, three hundred ninety-seven million, four hundred fifty-seven thousand, six hundred twenty".