1561897651901 has 16 divisors (see below), whose sum is σ = 1630342200960. Its totient is φ = 1494982681920.

The previous prime is 1561897651889. The next prime is 1561897651933. The reversal of 1561897651901 is 1091567981651.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561897651901 is a prime.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561897651991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1475936 + ... + 2302646.

It is an arithmetic number, because the mean of its divisors is an integer number (101896387560).

Almost surely, 2^{1561897651901} is an apocalyptic number.

It is an amenable number.

1561897651901 is a deficient number, since it is larger than the sum of its proper divisors (68444549059).

1561897651901 is an equidigital number, since it uses as much as digits as its factorization.

1561897651901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827636.

The product of its (nonzero) digits is 4082400, while the sum is 59.

The spelling of 1561897651901 in words is "one trillion, five hundred sixty-one billion, eight hundred ninety-seven million, six hundred fifty-one thousand, nine hundred one".