1561641928 has 64 divisors (see below), whose sum is σ = 3728332800. Its totient is φ = 595475520.

The previous prime is 1561641919. The next prime is 1561641941. The reversal of 1561641928 is 8291461651.

It is a super-2 number, since 2×1561641928² = 4877451022575114368, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1983 + ... + 55921.

It is an arithmetic number, because the mean of its divisors is an integer number (58255200).

Almost surely, 2^1561641928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561641928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1864166400).

1561641928 is an abundant number, since it is smaller than the sum of its proper divisors (2166690872).

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

1561641928 is a wasteful number, since it uses less digits than its factorization.

1561641928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54010 (or 54006 counting only the distinct ones).

The product of its digits is 103680, while the sum is 43.

The square root of 1561641928 is about 39517.6154138885. The cubic root of 1561641928 is about 1160.1847525785.

The spelling of 1561641928 in words is "one billion, five hundred sixty-one million, six hundred forty-one thousand, nine hundred twenty-eight".