15978977280 has 1152 divisors, whose sum is σ = 70648381440. Its totient is φ = 3255828480.

The previous prime is 15978977251. The next prime is 15978977291. The reversal of 15978977280 is 8277987951.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 339978217 + ... + 339978263.

It is an arithmetic number, because the mean of its divisors is an integer number (61326720).

Almost surely, 2^15978977280 is an apocalyptic number.

15978977280 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 15978977280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35324190720).

15978977280 is an abundant number, since it is smaller than the sum of its proper divisors (54669404160).

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

15978977280 is a wasteful number, since it uses less digits than its factorization.

15978977280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 63.

The spelling of 15978977280 in words is "fifteen billion, nine hundred seventy-eight million, nine hundred seventy-seven thousand, two hundred eighty".