79251781 has 4 divisors (see below), whose sum is σ = 90573472. Its totient is φ = 67930092.

The previous prime is 79251737. The next prime is 79251787. The reversal of 79251781 is 18715297.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 79251781 - 2¹³ = 79243589 is a prime.

It is a super-2 number, since 2×79251781² = 12561689583343922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79251787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5660835 + ... + 5660848.

It is an arithmetic number, because the mean of its divisors is an integer number (22643368).

Almost surely, 2^79251781 is an apocalyptic number.

It is an amenable number.

79251781 is a deficient number, since it is larger than the sum of its proper divisors (11321691).

79251781 is a wasteful number, since it uses less digits than its factorization.

79251781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11321690.

The product of its digits is 35280, while the sum is 40.

The square root of 79251781 is about 8902.3469377462. The cubic root of 79251781 is about 429.5394040490.

The spelling of 79251781 in words is "seventy-nine million, two hundred fifty-one thousand, seven hundred eighty-one".