1909561901 has 8 divisors (see below), whose sum is σ = 2122788864. Its totient is φ = 1705811760.

The previous prime is 1909561891. The next prime is 1909561903. The reversal of 1909561901 is 1091659091.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1909561901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1909561903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2368781 + ... + 2369586.

It is an arithmetic number, because the mean of its divisors is an integer number (265348608).

Almost surely, 2^1909561901 is an apocalyptic number.

It is an amenable number.

1909561901 is a deficient number, since it is larger than the sum of its proper divisors (213226963).

1909561901 is a wasteful number, since it uses less digits than its factorization.

1909561901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4738411.

The product of its (nonzero) digits is 21870, while the sum is 41.

The square root of 1909561901 is about 43698.5343118050. The cubic root of 1909561901 is about 1240.6365750292.

The spelling of 1909561901 in words is "one billion, nine hundred nine million, five hundred sixty-one thousand, nine hundred one".