1561914720 has 144 divisors (see below), whose sum is σ = 5409920880. Its totient is φ = 410268672.

The previous prime is 1561914719. The next prime is 1561914727. The reversal of 1561914720 is 274191651.

1561914720 is a `hidden beast` number, since 1 + 5 + 619 + 14 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561914727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88386 + ... + 104574.

It is an arithmetic number, because the mean of its divisors is an integer number (37568895).

Almost surely, 2^1561914720 is an apocalyptic number.

1561914720 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 1561914720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2704960440).

1561914720 is an abundant number, since it is smaller than the sum of its proper divisors (3848006160).

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

1561914720 is a wasteful number, since it uses less digits than its factorization.

1561914720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16277 (or 16266 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 1561914720 is about 39521.0667872212. The cubic root of 1561914720 is about 1160.2523034229.

The spelling of 1561914720 in words is "one billion, five hundred sixty-one million, nine hundred fourteen thousand, seven hundred twenty".