649533837261 has 16 divisors (see below), whose sum is σ = 870038117568. Its totient is φ = 431026838400.

The previous prime is 649533837193. The next prime is 649533837301. The reversal of 649533837261 is 162738335946.

649533837261 is a nontrivial binomial coefficient, being equal to C(1139767, 2).

It is not a de Polignac number, because 649533837261 - 2¹³ = 649533829069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649533837661) 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, 3324321 + ... + 3514281.

It is an arithmetic number, because the mean of its divisors is an integer number (54377382348).

Almost surely, 2^649533837261 is an apocalyptic number.

649533837261 is the 1139766-th triangular number.

It is an amenable number.

649533837261 is a deficient number, since it is larger than the sum of its proper divisors (220504280307).

649533837261 is a wasteful number, since it uses less digits than its factorization.

649533837261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195212.

The product of its digits is 19595520, while the sum is 57.

The spelling of 649533837261 in words is "six hundred forty-nine billion, five hundred thirty-three million, eight hundred thirty-seven thousand, two hundred sixty-one".