1399661280 has 288 divisors, whose sum is σ = 4956614208. Its totient is φ = 359424000.

The previous prime is 1399661273. The next prime is 1399661299. The reversal of 1399661280 is 821669931.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8914962 + ... + 8915118.

It is an arithmetic number, because the mean of its divisors is an integer number (17210466).

Almost surely, 2^1399661280 is an apocalyptic number.

1399661280 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 1399661280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2478307104).

1399661280 is an abundant number, since it is smaller than the sum of its proper divisors (3556952928).

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

1399661280 is a wasteful number, since it uses less digits than its factorization.

1399661280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370 (or 359 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 1399661280 is about 37412.0472575346. The cubic root of 1399661280 is about 1118.5987152048.

It can be divided in two parts, 139966 and 1280, that added together give a triangular number (141246 = T₅₃₁).

The spelling of 1399661280 in words is "one billion, three hundred ninety-nine million, six hundred sixty-one thousand, two hundred eighty".