133537691 has 6 divisors (see below), whose sum is σ = 155339820. Its totient is φ = 114460836.

The previous prime is 133537673. The next prime is 133537727. The reversal of 133537691 is 196735331.

It is not a de Polignac number, because 133537691 - 2⁶ = 133537627 is a prime.

It is a super-2 number, since 2×133537691² = 35664629835222962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133537631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1362581 + ... + 1362678.

It is an arithmetic number, because the mean of its divisors is an integer number (25889970).

Almost surely, 2^133537691 is an apocalyptic number.

133537691 is a deficient number, since it is larger than the sum of its proper divisors (21802129).

133537691 is an equidigital number, since it uses as much as digits as its factorization.

133537691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2725273 (or 2725266 counting only the distinct ones).

The product of its digits is 51030, while the sum is 38.

The square root of 133537691 is about 11555.8509422716. The cubic root of 133537691 is about 511.1338237106.

It can be divided in two parts, 133 and 537691, that added together give a 5-th power (537824 = 14⁵).

The spelling of 133537691 in words is "one hundred thirty-three million, five hundred thirty-seven thousand, six hundred ninety-one".