20149531 has 2 divisors, whose sum is σ = 20149532. Its totient is φ = 20149530.

The previous prime is 20149529. The next prime is 20149543. The reversal of 20149531 is 13594102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20149531 - 2¹ = 20149529 is a prime.

It is a super-2 number, since 2×20149531² = 812007199039922, which contains 22 as substring.

Together with 20149529, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 20149496 and 20149505.

It is not a weakly prime, because it can be changed into another prime (20149501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10074765 + 10074766.

It is an arithmetic number, because the mean of its divisors is an integer number (10074766).

Almost surely, 2^20149531 is an apocalyptic number.

20149531 is a deficient number, since it is larger than the sum of its proper divisors (1).

20149531 is an equidigital number, since it uses as much as digits as its factorization.

20149531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 20149531 is about 4488.8228969297. The cubic root of 20149531 is about 272.1165653431.

It can be divided in two parts, 201495 and 31, that multiplied together give a triangular number (6246345 = T₃₅₃₄).

The spelling of 20149531 in words is "twenty million, one hundred forty-nine thousand, five hundred thirty-one".