1961398457511 has 16 divisors (see below), whose sum is σ = 2647058206464. Its totient is φ = 1291673029184.

The previous prime is 1961398457507. The next prime is 1961398457537. The reversal of 1961398457511 is 1157548931691.

It is a cyclic number.

It is not a de Polignac number, because 1961398457511 - 2² = 1961398457507 is a prime.

It is a super-3 number, since 3×1961398457511³ (a number of 38 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961398457581) 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, 1366870 + ... + 2406476.

It is an arithmetic number, because the mean of its divisors is an integer number (165441137904).

Almost surely, 2^{1961398457511} is an apocalyptic number.

1961398457511 is a deficient number, since it is larger than the sum of its proper divisors (685659748953).

1961398457511 is a wasteful number, since it uses less digits than its factorization.

1961398457511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1047270.

The product of its digits is 8164800, while the sum is 60.

The spelling of 1961398457511 in words is "one trillion, nine hundred sixty-one billion, three hundred ninety-eight million, four hundred fifty-seven thousand, five hundred eleven".