67261961392921 has 3 divisors (see below), whose sum is σ = 67261969594261. Its totient is φ = 67261953191582.

The previous prime is 67261961392919. The next prime is 67261961392949. The reversal of 67261961392921 is 12929316916276.

The square root of 67261961392921 is 8201339.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 67261961392921 - 2¹ = 67261961392919 is a prime.

It is a super-2 number, since 2×67261961392921² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67261961392321) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4100670 + ... + 12302008.

Almost surely, 2^{67261961392921} is an apocalyptic number.

67261961392921 is the 8201339-th square number.

67261961392921 is the 4100670-th centered octagonal number.

It is an amenable number.

67261961392921 is a deficient number, since it is larger than the sum of its proper divisors (8201340).

67261961392921 is an frugal number, since it uses more digits than its factorization.

67261961392921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16402678 (or 8201339 counting only the distinct ones).

The product of its digits is 26453952, while the sum is 64.

The spelling of 67261961392921 in words is "sixty-seven trillion, two hundred sixty-one billion, nine hundred sixty-one million, three hundred ninety-two thousand, nine hundred twenty-one".